added hacker rank folder

please accept as hacktoberfest chaalange

Author: DSMalaviya

Hackerrank/Problem Solving/common_child.cpp

@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+using namespace std;
+int lcsHelper(char *s1, char *s2, int m, int n, int **dp)
+{
+    if (m == 0 || n == 0)
+    {
+        return 0;
+    }
+    if (dp[m][n] > -1)
+    {
+        return dp[m][n];
+    }
+    int ans;
+    if (s1[0] == s2[0])
+    {
+        ans = 1 + lcsHelper(s1 + 1, s2 + 1, m - 1, n - 1, dp);
+    }
+    else
+    {
+        int option1 = lcsHelper(s1 + 1, s2, m - 1, n, dp);
+        int option2 = lcsHelper(s1, s2 + 1, m, n - 1, dp);
+        ans = max(option1, option2);
+    }
+    dp[m][n] = ans;
+    return ans;
+}
+int lcs(char *s1, char *s2)
+{
+    int m = strlen(s1);
+    int n = strlen(s2);
+    int **dp = new int *[m + 1];
+    for (int i = 0; i <= m; i++)
+    {
+        dp[i] = new int[n + 1];
+        for (int j = 0; j <= n; j++)
+        {
+            dp[i][j] = -1;
+        }
+    }
+    int ans = lcsHelper(s1, s2, m, n, dp);
+    for (int i = 0; i <= m; i++)
+    {
+        delete[] dp[i];
+    }
+    delete[] dp;
+    return ans;
+}
+int main()
+{
+
+    char s1[5010], s2[5010];
+    cin >> s1 >> s2;
+    cout << lcs(s1, s2) << endl;
+    return 0;
+}

Hackerrank/Problem Solving/construct_the_array.cpp

@@ -0,0 +1,77 @@
+#include <bits/stdc++.h>
+#define MOD 1000000007
+using namespace std;
+
+vector<string> split_string(string);
+
+// Complete the countArray function below.
+long countArray(int n, int k, int x) {
+    // Return the number of ways to fill in the array.
+    long oneCount = 1;
+    long nonOneCount = 0;
+
+    for(int i=1;i<n;i++){
+        long prevOneCount = oneCount;
+        oneCount = (nonOneCount*(k-1))%MOD;
+        nonOneCount = (prevOneCount + ((k-2)*nonOneCount)%MOD)%MOD;
+    }
+    if(x==1){
+        return oneCount;
+    }else{
+        return nonOneCount;
+    }
+
+}
+
+int main()
+{
+    ofstream fout(getenv("OUTPUT_PATH"));
+
+    string nkx_temp;
+    getline(cin, nkx_temp);
+
+    vector<string> nkx = split_string(nkx_temp);
+
+    int n = stoi(nkx[0]);
+
+    int k = stoi(nkx[1]);
+
+    int x = stoi(nkx[2]);
+
+    long answer = countArray(n, k, x);
+
+    fout << answer << "\n";
+
+    fout.close();
+
+    return 0;
+}
+
+vector<string> split_string(string input_string) {
+    string::iterator new_end = unique(input_string.begin(), input_string.end(), [] (const char &x, const char &y) {
+        return x == y and x == ' ';
+    });
+
+    input_string.erase(new_end, input_string.end());
+
+    while (input_string[input_string.length() - 1] == ' ') {
+        input_string.pop_back();
+    }
+
+    vector<string> splits;
+    char delimiter = ' ';
+
+    size_t i = 0;
+    size_t pos = input_string.find(delimiter);
+
+    while (pos != string::npos) {
+        splits.push_back(input_string.substr(i, pos - i));
+
+        i = pos + 1;
+        pos = input_string.find(delimiter, i);
+    }
+
+    splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));
+
+    return splits;
+}

Hackerrank/Problem Solving/sam_and_substrings.cpp

@@ -0,0 +1,33 @@
+#include <bits/stdc++.h>
+#define MOD 1000000007
+using namespace std;
+
+// Complete the substrings function below.
+int substrings(string s) {
+    
+    long long lastValue = s[0]-'0';
+    long long totalSum = s[0] - '0';
+    for(int i=1;i<s.length();i++){
+        lastValue = (lastValue*10) + ((s[i]-'0')*(i+1));
+        lastValue = lastValue%MOD;
+        totalSum = (totalSum + lastValue)%MOD;
+    }
+    return totalSum;
+
+}
+
+int main()
+{
+    ofstream fout(getenv("OUTPUT_PATH"));
+
+    string n;
+    getline(cin, n);
+
+    int result = substrings(n);
+
+    fout << result << "\n";
+
+    fout.close();
+
+    return 0;
+}

Hackerrank/Problem Solving/sherlocks_and_anagrams.cpp

@@ -0,0 +1,51 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+// Complete the sherlockAndAnagrams function below.
+int sherlockAndAnagrams(string s) {
+    map<string,int>m;
+    int n = s.length();
+    for(int i=0;i<n;i++){
+        for(int j=0;j<n;j++){
+            string ans = "";
+            for(int k=i;k<=j;k++){
+                ans += s[k];
+            }
+            if(ans!=""){
+                sort(ans.begin(),ans.end());
+                m[ans]++;
+            }
+        }
+    }
+    int count = 0;
+    for(auto p:m){
+        if(p.second>=2){
+            count+=((p.second)*(p.second-1))/2;
+        }
+    }
+
+    return count;
+}
+
+int main()
+{
+    ofstream fout(getenv("OUTPUT_PATH"));
+
+    int q;
+    cin >> q;
+    cin.ignore(numeric_limits<streamsize>::max(), '\n');
+
+    for (int q_itr = 0; q_itr < q; q_itr++) {
+        string s;
+        getline(cin, s);
+
+        int result = sherlockAndAnagrams(s);
+
+        fout << result << "\n";
+    }
+
+    fout.close();
+
+    return 0;
+}

Hackerrank/Problem Solving/the_maximum_subarray.cpp

@@ -0,0 +1,64 @@
+#include <bits/stdc++.h>
+using namespace std;
+int max_subsequence(int a[], int n)
+{
+    int m = a[0], s = 0;
+    for (int i = 0; i < n; i++)
+    {
+        if (m < a[i])
+        {
+            m = a[i];
+        }
+        if (a[i] >= 0)
+        {
+            s += a[i];
+        }
+    }
+    if (m >= 0)
+    {
+        return s;
+    }
+    else
+    {
+        return m;
+    }
+}
+int maxSubArraySum(int a[], int n)
+{
+    int f = a[0];
+    int ans = f;
+    for(int i = 1;i < n ; i++){
+        f = max(a[i], f + a[i]);
+        ans = max(ans, f);
+    }
+    return ans;
+}
+vector<int> maximum_subarray(int a[], int n)
+{
+    vector<int> ans;
+    ans.push_back(maxSubArraySum(a, n));
+    ans.push_back(max_subsequence(a, n));
+    return ans;
+}
+int main()
+{
+    int t;
+    cin >> t;
+    while (t--)
+    {
+        int n;
+        cin >> n;
+        int a[n];
+        for (int i = 0; i < n; i++)
+        {
+            cin >> a[i];
+        }
+
+        vector<int> ans = maximum_subarray(a, n);
+        for(int i=0;i<ans.size();i++){
+            cout<<ans[i]<<" ";
+        }
+        cout<<endl;
+    }
+    return 0;
+}

Hackerrank/Project_Euler/q1.cpp

@@ -0,0 +1,29 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+typedef long long int ll;
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    ll t;
+    cin>>t;
+    while(t--)
+    {
+        ll n;
+        cin>>n;
+        ll s = 0;
+        n -= 1;
+        ll three = n/3;
+        ll five = n/5;
+        ll fifteen = n/15;
+        three = (three*(three+1))/2;
+        five = (five*(five + 1))/2;
+        fifteen = (fifteen*(fifteen+1))/2;
+        s = s + (three*3) + (five*5) - (fifteen*15);
+
+        cout<<s<<"\n";
+    }
+    return 0;
+}

Hackerrank/Project_Euler/q10.cpp

@@ -0,0 +1,59 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+typedef long long int ll;
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    ///////////////////////////////////////////seive
+    ll size = 1e6+1;
+    bool isprime[size];
+    for(ll i=0;i<size;i++)
+    {
+        isprime[i] = true;
+    }
+    isprime[0] = isprime[1] = false;
+    for(ll i=2;i*i<size;i++)
+    {
+        if(isprime[i])
+        {
+            for(ll j=i*i;j<size;j+=i)
+                isprime[j] = false;
+        }
+    }
+    set <ll> s;
+    for(ll i=0;i<size;i++)
+    {
+        if(isprime[i])
+            s.insert(i);
+    }
+    ll sizea = s.size();
+    ll a[sizea],b[sizea],f = 0;
+    for(auto it : s)
+    {
+        a[f++] = it;
+    }
+    b[0] = a[0];
+    for(ll i=1;i<sizea;i++)
+    {
+        b[i] = a[i];
+        b[i] += b[i-1];
+    }
+    ///////////////////////////////////////////
+    ll t;
+    cin>>t;
+    while(t--)
+    {
+        ll n;
+        cin>>n;
+        ll index = lower_bound(a,a+sizea,n) - a;
+        if(a[index] != n)
+        {
+            index -= 1;
+        }
+        cout<<b[index]<<"\n";
+    }
+    return 0;
+}