Striver's A2Z DSA Sheet

Contents

Step	Topic	Questions
1	Basics	22
2	Sorting Techniques	7
3	Arrays	40
4	Binary Search	32
5	Strings 1	15
6	Linked Lists	10
15	Graphs	40
	TOTAL	202

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Step 3 : Arrays (40/40)

Lec 1 : Easy (14/14)

S No	Problem	Difficulty	Solution
1	Largest Element in an Array	Easy	File
2	Second Largest Element in an Array w/o Sorting	Easy	File
3	Check if the array is sorted	Easy	File
4	Remove Duplicates from Sorted Array	Easy	File
5	Left Rotate an array by one place	Easy	File
6	Left rotate an array by D places	Easy	File
7	Move Zeroes to end	Easy	File
8	Linear Search	Easy	File
9	Find the Union	Medium	File
10	Find missing number in an array	Easy	File
11	Maximum Consecutive Ones	Easy	File
12	Find number occurring once, others twice	Medium	File
13	Longest subarray with sum K (positives)	Medium	File
14	Longest subarray with sum K (positives + negatives)	Medium	File

Lec 2 : Medium (14/14)

S No	Problem	Difficulty	Solution
1	Two Sum	Medium	File
2	Sort Colors	Medium	File
3	Majority Element (>n/2)	Easy	File
4	Maximum Subarray Sum (Kadane's)	Easy	File
5	Print Max Subarray Sum	Medium	File
6	Stock Buy & Sell	Easy	File
7	Rearrange Array by Sign (2 versions)	Medium	File
8	Next Permutation	Medium	File
9	Leaders in Array	Easy	File
10	Longest Consecutive Sequence	Medium	File
11	Set Matrix Zeroes	Medium	File
12	Rotate Matrix by 90 degrees	Medium	File
13	Print the matrix in spiral manner	Medium	File
14	Count subarrays with given sum	Easy	File

Lec 3 : Hard (12/12)

S No	Problem	Difficulty	Solution
1	Pascal's Triangle	Medium	File
2	Majority Element (>n/3)	Medium	File
3	Three Sum	Medium	File
4	Four Sum	Medium	File
5	Longest Subarray with Zero Sum	Medium	File
6	Subarray with XOR K	Medium	File
7	Merge Overlapping Intervals	Medium	File
8	Merge Two Sorted Arrays Without Extra Space	Medium	File
9	Repeat and Missing Number	Medium	File
10	Count Inversions	Hard	File
11	Reverse Pairs	Hard	File
12	Max Product Subarray	Medium	File

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Step 4: Binary Search (32/32)

Lec 1: BS on 1D Arrays (13/13)

S No	Problem	Difficulty	Solution
1	Binary Search to find X in sorted array	Easy	File
2	Implement Lower Bound	Easy	File
3	Implement Upper Bound	Easy	File
4	Search Insert Position	Easy	File
5	Floor/Ceil in Sorted Array	Medium	File
6	First or last occurrence of number in sorted array	Easy	File
7	Count occurrences of a number in a sorted array	Easy	File
8	Search in Rotated Sorted Array I	Medium	File
9	Search in Rotated Sorted Array II	Medium	File
10	Find minimum in Rotated Sorted Array	Medium	File
11	Find out how many times has an array been rotated	Easy	File
12	Single element in a Sorted Array	Easy	File
13	Find peak element	Hard	File

Lec 2: BS on Answers (14/14)

S No	Problem	Difficulty	Solution
1	Find square root of a number in log n	Medium	File
2	Find the Nth root of a number using binary search	Medium	File
3	Koko Eating Bananas	Hard	File
4	Minimum days to make M bouquets	Hard	File
5	Find the smallest Divisor	Easy	File
6	Capacity to Ship Packages within D Days	Hard	File
7	Kth Missing Positive Number	Easy	File
8	Aggressive Cows	Hard	File
9	Book Allocation Problem	Hard	File
10	Split array – Largest Sum	Hard	File
11	Painter’s partition	Hard	File
12	Minimize Max Distance to Gas Station	Hard	File
13	Median of 2 sorted arrays	Hard	File
14	Kth element of 2 sorted arrays	Medium	File

Lec 3: BS on 2D Arrays (5/5)

S No	Problem	Difficulty	Solution
1	Find the row with maximum number of 1’s	Easy	File
2	Search in a 2 D matrix	Medium	File
3	Search in a row and column wise sorted matrix	Medium	File
4	Find Peak Element (2D Matrix)	Hard	File
5	Matrix Median	Hard	File

Step 5 : Strings I (15/15)

Lec 1 : Basic & Easy String Problems (7/7)

S No	Problem	Difficulty	Solution
1	Remove outermost Parenthesis	Easy	File
2	Reverse words in a given string / Palindrome Check	Easy	File
3	Largest odd number in a string	Easy	File
4	Longest Common Prefix	Easy	File
5	Isomorphic String	Easy	File
6	Check whether one string is a rotation of another	Medium	File
7	Check if two strings are anagram of each other	Medium	File

Lec 2 : Medium String Problems (8/8)

S No	Problem	Difficulty	Solution
1	Sort Characters by frequency	Easy	File
2	Maximum Nesting Depth of Parenthesis	Easy	File
3	Roman Number to Integer and vice versa	Easy	File
4	Implement Atoi	Medium	File
5	Count Number of Substrings	Medium	-
6	Longest Palindromic Substring (Do it without DP)	Hard	File
7	Sum of Beauty of all substring	Medium	File
8	Reverse Every Word in A String	Easy	File

Step 6 : Linked Lists (10/31)

Lec 1 : Learn Linked Lists (5/5)

S No	Problem	Difficulty	Solution
1	Intro to LL	Easy	File
2	Inserting a node in LL	Easy	File
3	Deleting a node in LL	Easy	File
4	Find length of LL	Medium	File
5	Search an element in LL	Medium	File

Lec 2 : Learn Doubly Linked Lists (4/4)

S No	Problem	Difficulty	Solution
1	Intro to LL	Easy	File
2	Inserting a node in LL	Easy	File
3	Deleting a node in LL	Easy	File
4	Find length of LL	Medium	File
5	Search an element in LL	Medium	File

Lec 3 : Medium Problems of LL (1/15)

S No	Problem	Diff	Solution
1	Middle of LL (Tortoise-Hare Method)	Easy	File
2	Reverse LL (Iterative)	Easy	File
3	Reverse LL (Recursive)	Easy	File
4	Detect a loop in LL	Medium	File
5	Find the starting point in LL	Medium	File
6	Length of Loop in LL	Easy	File
7	Check if LL is palindrome or not	Medium	File
8	Segregate odd and even nodes in LL	Medium	File
9	Remove Nth node from the back	Medium	File
10	Delete the middle node of LL	Medium	File
11	Sort LL	Medium	File
12	Sort LL of 0,1,2 by changing links	Medium	File
13	Find the intersection point of Y LL	Medium	File
14	Add 1 to a number represented by LL	Medium	File
15	Add 2 numbers in LL	Medium	File

Lec 4 : Medium Problems of DLL

Lec 5 : Hard Problems of LL

Step 15 : Graphs (15/15)

Lec 2 : Problems on BFS/DFS (14/14)

S No	Problem	Difficulty	Solution
1	Number of Provinces	Medium	File
2	Number of Provinces (Adjacency Matrix)	Hard	same as previous
3	Rotten Oranges	Medium	File
4	Flood Fill	Hard	File
5	Cycle Detection in Graph (BFS)	Hard	File
6	Cycle Detection in Graph (DFS)	Hard	File
7	Shortest Distance from 0 in Binary Grid	Medium	File
8	Surrounded Regions	Hard	File
9	True Enclaves	Hard	File
10	Word Ladder 1	Hard	File
11	Word Ladder 2	Hard	File
12	Distinct Islands	Hard	File
13	Bipartite Graph	Medium	File
14	Cycle Detection in Directed Graph	Hard	File

Lec 3 : Topological Sort (7/7)

S No	Problem	Difficulty	Solution
1	Topo Sort	Hard	File
2	Kahn's Algorithm	Hard	File
3	Cycle Detection in Directed Graph (BFS)	Hard	File
4	Course Schedule - 1	Hard	File
5	Course Schedule - 2	Hard	File
6	Find Eventual Safe States	Hard	File
7	Alien Dictionary	Hard	File

Lec 4 : Shortest Path Algorithms (13/13)

S No	Problem	Difficulty	Solution
1	Shortest Path in UG with unit weights	Hard	File
2	Shortest Path in DAG	Hard	File
3	Dijkstra's Algorithm	Hard	File
4	Why priority Queue is used in Dijkstra	Medium	File
5	Shortest path in a binary maze	Medium	File
6	Path with minimum effort	Medium	File
7	Cheapest flights within k stops	Hard	File
8	Network Delay time	Medium	File
9	Number of ways to arrive at destination	Medium	File
10	Multiplication Graph	Hard	File
11	Bellman Ford Algorithm	Hard	File
12	Floyd Warshal Algorithm	Hard	File
13	City with the min neighbors in threshold	Hard	File

Lec 5 : Shortest Path Algorithms (4/11)

S No	Problem	Difficulty	Solution
1	Minimum Spanning Tree	Hard	-
2	Prim's Algorithm	Hard	-
3	Disjoint Set [Union by Rank]	Hard	-
4	Disjoint Set [Union by Size]	Hard	-
5	Kruskal's Algorithm	Hard	-
6	Number of Ops to Make Network Connected	Medium	-
7	Most Stones removed w/ Same Rows or Columns	Medium	-
8	Accounts Merge	Hard	-
9	Number of Island II	Hard	-
10	Making a Large Island	Hard	-
11	Swim in Rising Water	Hard	-

Lec 6 : Other Algorithms

S No	Problem	Difficulty	Solution
1	Bridges in Graph	Hard	-
2	Articulation Point	Hard	-
3	Kosaraju's Algorithm	Hard	-