Return the maximized sum.
public class Solution {
public int ArrayPairSum(int[] nums) {
int sum = 0;
Array.Sort(nums);
for (var i = 0; i < nums.Length; i += 2)
sum += nums[i];
return sum;
}
}
Write a function to determine if t is an anagram of s
Sort
public class Solution {
public bool IsAnagram(string s, string t) {
if (s.Length != t.Length)
return false;
char[] source = s.ToCharArray(), target = t.ToCharArray();
Array.Sort(source);
Array.Sort(target);
for (int i = 0; i <= source.Length - 1; i++)
if(source[i] != target[i])
return false;
return true;
}
}
Return the shuffled string.
Sorting
public class Solution {
public string RestoreString(string s, int[] indices) {
char[] resultChars = new char[s.Length];
for (int i = 0; i < indices.Length; i++)
{
resultChars[indices[i]] = s[i];
}
return new string(resultChars);
}
}
Array
public class Solution {
public IList<bool> KidsWithCandies(int[] candies, int extraCandies) {
int len = candies.Length;
bool[] result = new bool[len];
int max = 0;
for (int i = 0; i < len; i++)
max = Math.Max(max, candies[i]);
for (int j = 0; j < len; j++)
result[j] = candies[j] + extraCandies >= max;
return result;
}
}
Find all pairs of elements with the minimum absolute difference of any two elements.
public class Solution
{
public IList<IList<int>> MinimumAbsDifference(int[] arr)
{
Array.Sort(arr);
var dict = new Dictionary<int, List<(int, int)>>();
for (var i = 0; i < arr.Length - 1; i++)
{
var diff = arr[i + 1] - arr[i];
if (dict.ContainsKey(diff))
{
dict[diff].Add((arr[i], arr[i + 1]));
}
else
{
dict.Add(diff, new List<(int, int)> { (arr[i], arr[i + 1]) });
}
}
return dict[dict.Keys.Min()].Select(x => new[] { x.Item1, x.Item2 }).ToArray();
}
}
Recursion
public class Solution {
public TreeNode IncreasingBST(TreeNode root) {
var list = new List<TreeNode>();
Search(root, list);
for (var i = 0; i < list.Count; i++) {
list[i].left = null;
list[i].right = i < list.Count - 1 ? list[i + 1] : null;
}
return list.First();
}
void Search(TreeNode root, List<TreeNode> list) {
if (root == null) {
return;
}
Search(root.left, list);
list.Add(root);
Search(root.right, list);
}
}
Return the weight of this stone
Heap
public class Solution {
public int LastStoneWeight(int[] stones) {
List<int> stoneList = new List<int>(stones);
return stoneHelper(stoneList);
}
public int stoneHelper(List<int> stones) {
if(stones.Count == 0 )
return 0;
else if (stones.Count == 1)
return stones[0];
else {
int max = stones.Max();
stones.Remove(max);
int sMax = stones.Max();
stones.Remove(sMax);
if (sMax < max) {
stones.Add(max-sMax);
}
return stoneHelper(stones);
}
}
}
Write a function to compute their intersection.
Sort
public class Solution
{
public int[] Intersection(int[] nums1, int[] nums2)
{
if (nums1.Length > nums2.Length) return Intersection(nums2, nums1);
var elements = new HashSet<int>();
var result = new HashSet<int>();
foreach (var num in nums1)
{
elements.Add(num);
}
foreach (var num in nums2)
{
if (elements.Contains(num))
{
result.Add(num);
}
}
return result.ToArray();
}
}
Return all lucky numbers in the matrix in any order.
public class Solution {
public IList<int> LuckyNumbers (int[][] matrix)
{
int m = matrix.Length;
int n = matrix[0].Length;
var result = new List<int>();
var minRows = new int[m];
var maxCols = new int[n];
for(int i = 0; i < m; i++)
minRows[i] = matrix[i].Min();
for(int i = 0; i < n; i++)
{
int max = int.MinValue;
for(int j = 0; j < m; j++)
max = Math.Max(max, matrix[j][i]);
maxCols[i] = max;
}
for(int i = 0; i < m; i++)
{
for(int j = 0; j < n; j++)
{
if(minRows[i] == matrix[i][j] && maxCols[j] == matrix[i][j])
result.Add(matrix[i][j]);
}
}
return result;
}
}
Return the index if the target is found. If not, return the index where it would be if it were inserted in order.
Binary Search
public class Solution {
public int SearchInsert(int[] nums, int target) {
int i = nums.ToList().BinarySearch(target);
return i >= 0 ? i: ~i;
}
}
Find all unique triplets in the array which gives the sum of zero.
Two pointers
public class Solution {
public IList<IList<int>> ThreeSum(int[] nums) {
Array.Sort(nums);
var result = new List<IList<int>>();
var n = nums.Length;
for (int i = 0; i < n; i++) {
if (i > 0 && nums[i - 1] == nums[i]) continue;
var left = i + 1;
var right = n - 1;
while (left < right) {
var sum = nums[i] + nums[left] + nums[right];
if (sum == 0) {
result.Add(new List<int>() { nums[i], nums[left], nums[right] });
while (left < right && nums[left] == nums[left + 1]) left++;
while (left < right && nums[right] == nums[right - 1]) right--;
left++;
right--;
} else if (sum < 0) {
left++;
} else {
right--;
}
}
}
return result;
}
}
Find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
public class Solution {
public int MaxSubArray(int[] nums) {
int maxSum = 0;
int curSum = 0;
foreach(var i in nums){
maxSum += i;
}
for (var i = 0; i < nums.Count(); i++)
{
curSum += nums[i];
if(maxSum < curSum)
{
maxSum = curSum;
}
if(curSum < 0)
{
curSum = 0;
}
}
return maxSum;
}
}
Calculate Money in Leetcode Bank
public class Solution {
public int TotalMoney(int n) {
int[] output = new int[n+1];
output[1] = 1;
for (int i = 2; i <= n; i++)
{
if (i > 7 && i % 7 == 1)
output[i] = output[i - 7] + 1;
else
output[i] = output[i - 1] + 1;
}
return output.Sum();
}
}
public class Solution {
public bool HasCycle(ListNode head)
{
if(head == null)
return false;
ListNode slow = head;
ListNode fast = head.next;
while(slow!=null && fast!=null && slow!=fast)
{
slow = slow?.next;
fast = fast?.next?.next;
}
if(slow == fast && slow!=null)
return true;
return false;
}
}
Calculate Hamming Distance
Math
public class Solution {
public int HammingDistance(int x, int y) {
var z = x ^ y;
var count = 0;
while (z > 0) {
count += z & 1;
z >>= 1;
}
return count;
}
}
Invert a binary tree.
public class Solution { public TreeNode InvertTree(TreeNode root) { if (root == null) return root;
if (root.left != null || root.right != null)
{
TreeNode temp = root.left;
root.left = root.right;
root.right = temp;
InvertTree(root.left);
InvertTree(root.right);
}
return root;
}
}
return the preorder traversal of its nodes' values.
public class Solution {
public IList<int> Preorder(Node root) {
IList<int> preOrder = new List<int>();
Stack<Node> s = new Stack<Node>();
Node tmp;
s.Push(root);
while (s.TryPop(out tmp) && tmp != null)
{
preOrder.Add(tmp.val);
for (int i = tmp.children.Count - 1; i >= 0; i--)
{
s.Push(tmp.children[i]);
}
}
return preOrder;
}
}
CRUD without Entity Framework in ASP.NET Core mvc
CRUD without Entity Framework in ASP.NET Core mvc
Range Sum of BST
Tree
public class Solution {
public int RangeSumBST(TreeNode root, int L, int R) {
if (root == null) return 0;
var sum = 0;
if (L <= root.val && root.val <= R) {
sum = root.val;
}
var left = RangeSumBST(root.left, L, R);
var right = RangeSumBST(root.right, L, R);
return sum + left + right;
}
}
Constructing a new DBContext
ASP.NET Core MVC
ASP.NET Core MVC
Return the smallest index i that satisfies A[i] == i. Return -1 if no such i exists.
Array
public class Solution
{
private int Helper(int[] nums, int left, int right)
{
int res = int.MaxValue;
while (left < right)
{
int mid = left + (right - left) / 2;
int midItem = nums[mid];
if (midItem == mid)
{
res = Math.Min(res, mid);
right = mid;
continue;
}
if (midItem > mid)
{
right = mid;
continue;
}
left = mid + 1;
}
if (nums[left] == left)
{
res = Math.Min(res, left);
}
if (nums[right] == right)
{
res = Math.Min(res, right);
}
return res == int.MaxValue ? -1 : res;
}
public int FixedPoint(int[] nums)
{
return Helper(nums, 0, nums.Length - 1);
}
}
Remove duplicates from Sorted Array
Array
public class Solution {
public int RemoveDuplicates(int[] nums) {
if (nums == null || nums.Length == 0)
return 0;
else if (nums.Length == 1)
return 1;
int index1 = 0,
index2 = 1;
while(index2 <= nums.Length - 1)
if(nums[index1] == nums[index2])
index2++;
else
nums[++index1] = nums[index2++];
return ++index1;
}
}
Find out how many numbers in the array are smaller than it.
Array
public class Solution {
public int[] SmallerNumbersThanCurrent(int[] nums) {
int[] freq = new int[101], result = new int[nums.Length];
foreach(var num in nums)
freq[num]++;
for(int i = 0; i <= 100; i++)
freq[i] = i == 0 ? freq[i] : freq[i] + freq[i - 1];
for(int i = 0; i < nums.Length; i++)
result[i] = nums[i] == 0 ? 0 : freq[nums[i] - 1];
return result;
}
}
Return the sorted array
Array
public class Solution {
public int[] FrequencySort(int[] nums) {
var dict = new Dictionary<int,int>();
foreach (var n in nums)
{
if (!dict.ContainsKey(n))
dict.Add(n, 0);
dict[n]++;
}
return dict.OrderBy(d => d.Value).ThenByDescending(d => d.Key)
.SelectMany(d => Enumerable.Repeat(d.Key, d.Value).ToArray()).ToArray();
}
}
Sort in specific order
Array
public int[] RelativeSortArray(int[] arr1, int[] arr2) {
if(arr2.Length <= 1)
return arr2;
int z = 0;
int[] arr3 = new int[arr1.Length];
for(int y=0; y < arr2.Length; y++){
for(int i=0; i< arr1.Length; i++) {
if(arr1[i] == arr2[y])
arr3[z++] = arr2[y];
}
}
int m = z;
for(int i=0; i<arr1.Length; i++){
if(Array.IndexOf(arr2, arr1[i])<0) {
arr3[z++] = arr1[i];
}
}
int temp = 0;
for (int write = m; write < arr3.Length; write++) {
for (int sort = m; sort < arr3.Length - 1; sort++) {
if (arr3[sort] > arr3[sort + 1]) {
temp = arr3[sort + 1];
arr3[sort + 1] = arr3[sort];
arr3[sort] = temp;
}
}
}
return arr3;
}
Find the duplicate characters in a string array.
Array
public class Solution {
public IList<string> CommonChars(string[] A)
{
int[,] chars = new int[A.Length, 26];
IList<string> result = new List<string>();
for (int i = 0; i < A.Length; i++)
{
foreach (var item in A[i])
{
chars[i, item - 'a']++;
}
}
for (int i = 0; i < 26; i++)
{
int min = Int32.MaxValue;
for (int j = 0; j < A.Length; j++)
{
if (chars[j, i] < min)
min = chars[j, i];
}
if (min > 0)
for (int j = 0; j < min; j++)
result.Add(((char)(i + 'a')).ToString());
}
return result;
}
}
Determine if a person could attend all meetings.
public class Solution {
public bool CanAttendMeetings(int[][] intervals) {
var sortedIntervals = intervals.OrderBy(I => I[1]).ToArray();
for (var i = 0; i < sortedIntervals.Length; i++) {
if (i + 1 < sortedIntervals.Length && sortedIntervals[i][1] > sortedIntervals[i+1][0]) {
return false;
}
}
return true;
}
}
Create a Shopping Cart with ASP.NET Core MVC
ASP.NET Core MVC
- Update CartController
var cart = SessionHelper.GetObjectFromJson<List>(HttpContext.Session, "cart"); ViewBag.cart = cart; ViewBag.total = cart.Sum(Item => Item.Product.Price * Item.Quantity);
Create a Shopping Cart with ASP.NET Core MVC
ASP.NET Core MVC
- Add a new controller "Cartcontroller"
- Add a new folder "Helper"
- Add a new class "SessionHelper"
- Install Nuget "Newtonsoft.Json"
- Update SessionHelper
public static class SessionHelper { public static void SetObjectAsJson(this ISession session, string key, object value) { session.SetString(key, JsonConvert.SerializeObject(value)); }
public static T GetObjectFromJson<T>(this ISession session, string key) { var value = session.GetString(key); return value == null ? default : JsonConvert.DeserializeObject<T>(value); }}
Create a Shopping Cart with ASP.NET Core MVC
ASP.NET Core MVC
- Delete Error.cshtml
- Add images into images folder
- Update ProductController
ProductModel productModel = new ProductModel(); ViewBag.products = productModel.findall();
- Add Empty Razor View Index.cshtml
- Update Index.html
Code...
- Create a Product folder in Views
- Move Index.cshtml to Product
- Update Startup.cs
pattern: "{controller=Product}/{action=Index}/{id?}";
Create a Shopping Cart with ASP.NET Core MVC
ASP.NET Core MVC
- Update ProductModel public List _products { get; set; } public List findall() { _products = new List { new Product() { Id = "1", Name = "flower1", Photo = "thumb1.jpg", Price = 2.80 }, new Product() { Id = "2", Name = "flower2", Photo = "thumb2.jpg", Price = 3.50 }, new Product() { Id = "3", Name = "flower3", Photo = "thumb3.jpg", Price = 4.45 }, new Product() { Id = "4", Name = "flower4", Photo = "thumb4.jpg", Price = 3.70 }, new Product() { Id = "5", Name = "flower5", Photo = "thumb5.jpg", Price = 5.00 } }; return _products; } public Product find(string id) { List products = findall(); var prod = products.Where(a => a.Id == id).FirstOrDefault(); return prod; }
Create a Shopping Cart with ASP.NET Core MVC
ASP.NET Core MVC
- Create an ASP.NET Core MVC project
- Delete HomeController.cs in the Controllers folder and Home in the Views folder
- Add a new controller "ProductController"
- Create a product class
- Update a product class
public string Id {get; set;} public string Name {get; set;} public double Price {get; set;} public string Photo {get; set;}
- Create an item class
public Product Product{get; set;} public int Quantity{get; set;}
- Add ViewModels folder
- Create ProductModel class
- Update ProductModel
Output the first numRows of Pascal's triangle.
Array
public class Solution {
public IList<IList<int>> Generate(int numRows) {
List<int>[] results = new List<int>[numRows];
if (numRows != 0)
{
results[0] = new List<int>();
results[0].Add(1);
if (numRows != 0)
{
for (int row = 1; row <= numRows - 1; row++)
{
results[row] = new List<int>();
results[row].Add(1);
if (row > 1)
for (int i = 1; i <= row - 1; i++)
results[row].Add(results[row - 1][i - 1] + results[row - 1][i]);
results[row].Add(1);
}
}
}
return results;
}
}
Return the day number of the year
String
- Convert string to DateTime,
- Calculate the day of the year
- Convert String to DateTime
- Calculate the day of year
public class Solution {
public int DayOfYear(string date)
{
DateTime d = DateTime.Parse(date);
return d.DayOfYear;
}
}
Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
Stack
public class MinStack {
Stack<int> minStack = new Stack<int>();
Stack<int> stack = new Stack<int>();
/** initialize your data structure here. */
public MinStack() {
}
public void Push(int x) {
stack.Push(x);
if (!minStack.Any()) {
minStack.Push(x);
} else {
if (minStack.Peek() >= x) {
minStack.Push(x);
}
}
}
public void Pop() {
var x = stack.Pop();
if (minStack.Peek() == x) {
minStack.Pop();
}
}
public int Top() {
return stack.Peek();
}
public int GetMin() {
return minStack.Peek();
}
}
Program to determine if the input string is valid or not
String, Stack
Check if Stack is empty.
public bool IsValid(string s) {
Stack<char> sign = new Stack<char>();
if (String.IsNullOrEmpty(s))
{
return true;
}
foreach (var item in s.ToCharArray())
{
if(sign.Count() == 0){
sign.Push(item);
}else{
if (sign.Peek() == '('){
if(item == ')'){
sign.Pop();
}else{
sign.Push(item);
}
}else if(sign.Peek() == '['){
if(item == ']'){
sign.Pop();
}else{
sign.Push(item);
}
}else if(sign.Peek() == '{'){
if(item == '}'){
sign.Pop();
}else{
sign.Push(item);
}
}
}
}
return sign.Count == 0;
}
Return the sum of num1 and num2
String
public string AddStrings(string num1, string num2) {
char[] output = new char[Math.Max(num1.Length, num2.Length) + 1];
bool carry = false;
int position = 0;
for (int first = num1.Length - 1, second = num2.Length - 1; first >= 0 || second >= 0; first--, second--){
int result = (first >= 0 ? num1[first] - '0' : 0) + (second >= 0 ? num2[second] - '0' : 0) + (carry ? 1 : 0);
carry = result >= 10;
output[(output.Length - 1) - position++] = (char)('0' + (result % 10));
}
if (carry){
output[0] = '1';
}
return new string(
output,
carry ? 0 : 1,
carry ? output.Length : output.Length - 1
);
}
Find the Fizz, Buzz, and FizzBuzz
Math
- Create a new List
- for loop through n
- if for multiples of three, output Fizz
- if for multiples of five, output Buzz,
- if for multiples of three and multiples of five, output FizzBuzz
public IList<string> FizzBuzz(int n) {
List<string> res = new List<string>();
for(int i = 1; i <= n; i++)
{
string str = "";
if(i % 3 == 0)
str = "Fizz";
if(i % 5 == 0)
str = str + "Buzz";
str = str == ""? i.ToString() : str;
res.Add(str);
}
return res;
}
Create a custome Login page in ASP.NET Core MVC
ASP.NET Core Web app (MVC)
- Update Startup.cs
services.addRazorPages(); app.UseAuthentication(); endpoints.MapRazorPages();
-
Change font
-
Add connection string
appsettings.json
- Add-Migration
Add-Migration "Initial-Create" Update-Databas
Create a custome Login page in ASP.NET Core MVC
ASP.NET Core Web app (MVC)
- Create a default Asp.net core MVC project
- Create a Customize one
- No authentication
- Customize application
-
Add New Scaffolded Identity
- Select existing layout
Views\Shared_Layout.cshtml
- Choose file to override
Account\Login, Account\Register
- Add Data Context:
Auth.System.Data.AuthDbContext
- Add User Class
ApplicationUser
- Update Startup.cs
Convert EPUB to PDF
Console App
- Install Nuget pacakge
- Load input EPUB file
- Create a instance of PdfSaveOptions
- call the ConvertEPUB method
var epub = System.IO.File.OpenRead(dataDir + fileName);
Aspose.Html.Saving.PdfSaveOptions pdfOption = new Aspose.Html.Saving.PdfSaveOptions();
Aspose.Html.Converters.Converter.ConvertEPUB(epub, pdfOption, dataDir + "EPUBtoPDF.pdf");
Find the number of Good pairts.
Array
Nested for loop, if
- Iterate through Nested for loop
- if nums[i] == nums[j] && i < j, good pairs add 1
public class Solution {
public int NumIdenticalPairs(int[] nums) {
int count = 0;
for(int i = 0; i < nums.Length -1; i++)
{
for(int j = 1; j < nums.Length; j++)
{
if(nums[i] == nums[j] && i < j)
{
count += 1;
}
}
}
return(count);
}
}
Return the array in the form [x1,y1,x2,y2,...,xn,yn]
Array
public class Solution {
public int[] Shuffle(int[] nums, int n) {
if(nums.Length == 0)
return nums;
int[] newArray = new int[2 * n];
int index1 = 0, index2 = n;
for(int i = 0; i < 2 * n; i++)
{
if(i % 2 == 0)
newArray[i] = nums[index1++];
else
newArray[i] = nums[index2++];
}
return newArray;
}
}
一行, 解決。
Return the wealth that the richest customer has
Array
public class Solution {
public int MaximumWealth(int[][] accounts) {
return accounts.Max(x => x.Sum());
}
}
今天要別注意在的是在建立新的 Array 時要使用 Clone() 方法
Array
public class Solution {
public IList<int> TransformArray(int[] arr) {
// 判斷是否需要建立新的 Array
int number = -1;
while (number < 0)
{
// 將 arr 的值 Clone 給 newArray
var newArray = (int[])arr.Clone();
number = 0;
// 判斷 newArray 中是否有需要變更的數字
for (int i = 1; i < arr.Length - 1; i++)
{
if ((newArray[i] < newArray[i - 1]) && (newArray[i] < newArray[i + 1]))
{
arr[i] = arr[i] + 1;
number -= 1;
}
if ((newArray[i] > newArray[i - 1]) && (newArray[i] > newArray[i + 1]))
{
arr[i] = arr[i] - 1;
number -= 1;
}
}
}
return arr;
}
}
Simple solution
Array
- For loop through int array
- nums[i] += nums[i-1];
public class Solution {
public int[] RunningSum(int[] nums) {
for(int i = 1; i < nums.Length; i++)
{
nums[i] += nums[i-1];
}
return nums;
}
}
雖然今天直接參考網友的解法, 但這跟我的原本的想法相同, 直接將 Array 剖半, 再判斷向左或向右查找。
public int FirstBadVersion(int n) {
int start = 1, end = n;
while (start < end) {
int mid = start + (end-start) / 2;
if (!IsBadVersion(mid)) start = mid + 1;
else end = mid;
}
return start;
}
今天主要實作檔案的壓縮和解壓縮
Console App
今日使用 Console App 執行 OOP 程式
Console Application
- 輸入 First name
- 依據父類別判斷你的 Last name
今日是延續之前的 Single Number II, 主要修改 for loop increament, 而且也還要找出其他更好的方法。
- Sorting array
- Find the single number
public class Solution {
public int SingleNumber(int[] nums) {
// Sorting array
Array.Sort(nums);
int n = 0;
for (int i = 0; i < nums.Length; i+=3)
{
if (i == (nums.Length - 1))
{
n = nums[i];
return n;
}
else
{
// Find the single number
if (nums[i] != nums[i + 1])
{
n = nums[i];
return n;
}
}
}
return 0;
}
}
結合昨天的部分, 今天完整的使用 ASP.NET Identity 建立登入頁面
.NET Framework Web Application
- Create Database and data table
- Install Microsoft.AspNet.Identity.Owin
- Install Microsoft.Owin.Host.SystemWeb
- Add OWIN startup and authentication configuration
- Add Startup.cs
- Add a Web Form Login
今天只有編寫少部分的 C#, 主要是以學習 ASP.NET Identity 為主。
.NET Framework Web Application
- Create A ASP.NET Web Application Empty project
- Install Nuget package
- Add a Web Form Register
- replace content of Register.aspx
- Add Register.aspx.cs
- Add App_data
- Add a connection string in Web.Config
- Set as Start Page
這題要留意的就是使用 Array.Reverse(), 然後分段做 Reverse。只要懂概念, 這題就不難。
- Check if k is zero
- Use reverse
public void Rotate(int[] nums, int k)
{
// Check if k is zero
if (k == 0) return;
k %= nums.Length;
Array.Reverse(nums);
Array.Reverse(nums, 0, k );
Array.Reverse(nums, k, nums.Length - k);
}
Console Application
- Get project directory
- Create A instance of Document
- Encrypt PDF
- Save PDF
- Get project directory
- Create A instance of Document
- Decrypt PDF
- Save PDF
// Encryption
Document document = new Document(projectDirectory + "/Files/test.pdf");
document.Encrypt(userPassword, "ownerPassword", 0, CryptoAlgorithm.RC4x128);
document.Save(projectDirectory + "/Files/EncryptedPDF.pdf");
// Decryption
Document document2 = new Document(projectDirectory + "/Files/EncryptedPDF.pdf", userPassword2);
document2.Decrypt();
document2.Save("DecryptedPDF.pdf");
- Encrypt and Decrypt PDF Files using C#
- How do you get the current project directory from C# code when creating a custom MSBuild task?
今天也是透過著影片學習如何建立效能監控器。只要確實照著步驟做就能順利完成。
Windows Form App
- Add three lables
- Add a timer
- Set the properties
- Using System.Diagnostics
- Create a performanceCounter instance
- Set text value
Reference: How To Make A CPU Monitor in C#
由於已經先給定了要刪除的 node 不能是 tail node 的先決條件, 所以這題實在有點讓人摸不著頭緒, 如果想的複雜一點反而還可能出錯。:sob:
Console Application
- Node value is NextNode value
- Node next is NextNode next
public void DeleteNode(ListNode node) {
node.val = node.next.val;
node.next = node.next.next;
}
Reference: What is ListNode in C# ?
今天使用 Aspose.Words for .NET API, 程式碼的部分也很簡單。
Console Application
- Install Nuget package
- Set Directory path
- Load DOCX file
- Initialize HtmlSaveOptions
- Convert DOCX to HTML
static void Main(string[] args)
{
string dataDir = "\\Documents\\C#\\myProject\\100DaysOfCode\\FileConversion\\Files\\";
// Load the document from disk.
Document doc = new Document(dataDir + "test.docx");
// Set HtmlSaveOptions
HtmlSaveOptions options = new HtmlSaveOptions();
options.SaveFormat = SaveFormat.Html;
// Save the document into HTML
doc.Save(dataDir + "Document.html", options);
}
- Convert Word DOC or DOCX to HTML, MHTML in C# VB.NET
- Aspose.Words 20.12.0 (Nuget)
- Sample .doc and .docx download
找出轉換後最大的數且只有一次轉換的機會, 那就必須能知道當前的數字是否已經是最大的數。在判斷的過程中如果確認已經找到是最大的數, 則會 Swap two number 並且回傳轉換後的值。
- Convert integer to string
- Convert string to char array
- Check if the length of the array is greater than 1
public int MaximumSwap(int num) {
string s = Convert.ToString(num);
char[] ch = s.ToCharArray();
if(ch.Length > 1)
{
for (int i = 0; i < ch.Length-1; i++)
{
if(ch[i] != '9'){
int n = i;
for(int j = i + 1; j < ch.Length; j++)
{
if(ch[i] < ch[j] && ch[j] >= ch[n])
{
n = j;
}
}
if(n != i)
{
char[] ch1 = new char[1];
ch1[0] = ch[i];
ch[i] = ch[n];
ch[n] = ch1[0];
goto end;
}
}
}
end:
string s2 = new string(ch);
int parsed = Convert.ToInt32(s2);
return parsed;
}
else
{
return num;
}
}
即使這題只要使用 Array.Reverse 方法就能夠很輕易地解決, 我還是有想出自己的解法。 我的方式是使用 Swap two nubmers 結合 for loop 做左右互換, 而 for loop 只要執行 array s 長度的一半即可。
- Declare a one-dimensional char array c
- Reverse the char array s using for loop (half of array)
public void ReverseString(char[] s) {
char[] c = new char[1];
for (int i = 0; i < (s.Length) / 2; i++)
{
c[0] = s[i];
s[i] = s[s.Length - 1 - i];
s[s.Length - 1 - i] = c[0];
}
}
Reference: Array.Reverse Method
由左至右, 將發現的第一個 6 替換成 9, 結束。
- Convert integer to char array
- Find and place digit 6 to 9
- Convert char array to string
- Convert string to integer
public class Solution {
public int Maximum69Number (int num) {
char[] arr = num.ToString().ToCharArray();
for (int i=0; i < arr.Length; i++)
{
if (arr[i] == '6')
{
arr[i] = '9';
break;
}
}
string str = new string(arr);
int x = Int32.Parse(str);
return x;
}
}
今天這兩題的作法都是先將陣列進行排序, 在判斷是否和下一位數相同或是相異。如果能找出 Single Number, 那一定也能找出 Duplicate Number。
- Sorting array
- Find the single number
public int SingleNumber(int[] nums) {
// Sorting array
Array.Sort(nums);
for (int i = 0; i < nums.Length; i++)
{
if (i == ( nums.Length - 1))
{
return nums[i];
}
else
{
// Find the single number
if (nums[i] != nums[i + 1] && ((i + 1) % 2) == 1)
{
return nums[i];
}
}
}
return 1;
}
第一題算是非常簡單的題目, 只需要使用.ToLower() 就能完成。 第二題則複雜很多, 第一步會先將 Unsigned integer 轉換成一個 Binary string, 再使用 PadLeft() 以 '0' 填充 Binary string 左邊空格的部分, 填充後再將這個 Binary string 轉換成一個 char array。 當然, 這題最主要的還是要進行 Reverse bits, 最後使用了一個 for loop 結合 swap 的方式進行轉換。
- Convert uint to binary string
- Pad the binary string with leading zeros
- Convert to char array
- Reverse bits
public uint reverseBits(uint n) {
string binary = Convert.ToString(n, 2);
char[] ch = binary.PadLeft(32, '0').ToCharArray();
char[] c = new char[1];
for (int i=0; i < 16; i++) // 左右互換
{
c[0] = ch[i];
ch[i] = ch[31-i];
ch[31-i] = c[0];
}
string s = new string(ch);
uint parsed = Convert.ToUInt32(s, 2);
return parsed;
}
這題算是蠻簡單的, 只要使用兩個 for loop 就能找出組成 target 的兩個數。
public static int[] TwoSum(int[] nums, int target)
{
for (int i = nums.Length - 1; i >= 0; i--)
{
for (int j = 0; j <= i - 1; j++)
{
if (nums[j] + nums[i] == target)
{
int[] num = { j, i };
return num;
}
}
}
return null;
}
- Convert uint to string
- Convert string to char array
- Foreach char array and count the number of 1s
public int HammingWeight(uint n)
{
string s = Convert.ToString(n, 2); // Convert uint ot string
char[] ch = s.ToCharArray(); // Convert string to char array
int num = 0;
foreach (char c in ch) // Foreach char array and count the number of 1s
{
if(c == '1')
{
num = num + 1;
}
}
return num;
}
延續昨天未完的部分
今日參考 Youtube 上的教學影片建立 Windows Form App, 主要功能是對於 SQL Server 的資料進行 CRUD Operations, 未完的部分明天繼續
Windows Form App
- C# and SQL Server Perform SMART CRUD Operations with SEARCH (Edited Version Part 1/2)
- C# and SQL Server Perform SMART CRUD Operations with SEARCH (Edited Version Part 2/2)
- Download DS-Digital font
- Create Windows Form app
- Change background
- Add Labels
- Add button
- Change font
- Coding
private void timer1_Tick(object sender, EventArgs e)
{
<!-- Formatting times -->
label1.Text = DateTime.Now.ToString("dddd");
label2.Text = DateTime.Now.ToString("HH:mm");
label5.Text = DateTime.Now.ToString("tt");
label4.Text = DateTime.Now.ToString("yyyy");
label3.Text = DateTime.Now.ToString("ss");
label6.Text = DateTime.Now.ToString("MMM:dd");
}
private void Form1_Load(object sender, EventArgs e)
{
<!-- start a timer -->
timer1.Start();
}
private void button1_Click(object sender, EventArgs e)
{
<!-- Exit the application -->
Application.Exit();
}
Referencee: Make Digital Clock using C# Visual studio basics
參考網路資料後加入了標題以及輸入功能
Reference: Multiplication tables
SQL Server 連線測試程式。
簡易四則運算
參考網路文章建立簽名板, 因為程式中有些地方還需要進行除錯。
今天參考的是這篇 How to Upload Files and Save in Database in ASP.NET Core MVC, 文章寫得非常詳細, 只要按照他的步驟就能夠成功將檔案存入資料庫中。
Windows Form
第一天, 今天參考 Tim Corey 的影片 Working With The File System in C# - Managing Folders and Files, 學習如何對檔案進行存取。主要使用到 System.IO 的 Directory 類別。
Console Application
