Sorting  Binary search tree  Linked List  Arrays  Graphs  Dynamic Programming  String 
Matrix  Heaps  Miscellaneous 
Sorting algorithms 

1. Merge sort algorithm (Divide and Conquer)  Solution  
2. Quick sort algorithm (Divide and Conquer)  Solution  
3. Heap sort algorithm  Solution 
Binary search tree related questions 

1. Check if binary tree is balanced or not  Solution  
2. Zig Zag order traversal of tree.  Solution  
3. Prune all nodes of tree which are outside a range min and max.  Solution  
4. Find least common ancestor.  Solution  
5. Replace node with sum of children.  Solution  
6. Convert tree to DLL.  Solution  
7. Print last K nodes of binary search tree.  Solution  
8. Find pair of nodes with given sum.  Solution  
9. Level order traversal of tree.  Solution  
10.Build tree from given preorder and inroder traversal.  Solution  
11. Tree traversals without recursion.  Solution  
12. Find paths in binary search tree of given sum.  Solution  
13. Calculate number of trees with N nodes.  Solution  
14. Print right view of binary search tree.  Solution  
15. Vertical sum of binary search tree.  Solution 
Array related questions 

1. Find missing missing number in an array.  Solution  
2. Find repeated number in an array.  Solution  
3. Find all duplicate numbers in an array.  Solution  
4. Find One missing and one repeated number in an array.  Solution  
5. Smallest missing numbers in sorted array.  Solution  
6. Find element in first increasing and then decreasing array.  Solution  
7. Balanced subarray and zero sum sub array  Solution  
8. Rotate an array.  Solution  
9. Find element in rotated array.  Solution  
10.Sum of two numbers in array equal to K.  Solution  
11.In array of 0 and 1, find first occurrence of 1.  Solution  
12. Count sort.  Solution  
13. Find median of two sorted arrays.  Solution  
14. Find Kth smallest element in two sorted arrays.  Solution  
15. Find Kth smallest element in an array  Solution 
Matrix related questions 

1. Traverse a matrix in spiral order.  Solution  
2. Make row and column 1 if there is 1 in it.  Solution  
3. Search an element in matrix of sorted rows and columns.  Solution  
4. Rotate a matrix by 90 degree.  Solution  
5. Find maximum sub matrix with all ones.  Solution 
Dynamic programming questions 

1. Longest increasing subsequence.  Solution  
2. Longest common subsequence  Solution  
3. Subset sum problem  Solution  
4. Largest sum contiguous sub array.  Solution  
5. Minimum Jumps to reach end  Solution  
6. Coin change  Solution  
7. Minimum Number of coins for change.  Solution  
8. Matrix multiplication  Solution  
9. Edit distance  Solution  
10. Longest palindrome substring  Solution  
11. Longest palindrome subsequence  Solution  
12. Check if string in interleaved of two strings.  Solution 
String related questions 

1. Encoding of a string.  Solution  
2. Removal of duplicate characters.  Solution  
3. Find first duplicate character.  Solution  
4. Tokenize a string based on delimiter.  Solution  
5. Remove a particular combination of characters from string.  Solution  
6. Reverse words in a string.  Solution  
7. Check if string is combination of two strings.  Solution  
8. Break a string in meaningful dictionary words  Solution  
9. First non repeating character in stream of characters.  Solution  
10. Check if two strings are anagrams.  Solution  
11. Check if any anagram of string is palindrome.  Solution  
12. Print all anagrams together.  Solution 
Linked list related questions 

1. Find if there is loop in linked list.  Solution  
2. Add two numbers represented by linked lists.  Solution  
3. Merge two linked list.  Solution  
4. Find Nth node from end.  Solution  
5. Flatten a generic linked list.  Solution  
6. Delete a node from linked list.  Solution  
7. Check if linked list is palindrome.  Solution  
8. Clone linked list with arbitrary pointer.  Solution 
Heaps 

1. Merge K sorted arrays in one sorted array.  Solution  
2. Find K minimum elements in unsorted array.  Solution  
3. Find median in continuous stream of integers.  Solution  
4. Sliding window problem.  Solution  
5. Heaps basics.  Solution 

6. Find median of running stream of integers.  Solution 
Graphs 

1.Depth First Search.  Solution  
2. Breadth First Search.  Solution  
3. Topological sorting.  Solution  
4. Minimum spanning tree: Prim’s algorithm.  Solution  
5. Minimum spanning tree: Kruskal’s algorithm.  Solution  
6. Shortest Path algorithm: Dijkstra’s algorithm.  Solution  
7. Word ladder problem.  Solution  
8. Find connected components of graph.  Solution  
9. Detecting cycle in undirected graph.  Solution 
Miscellaneous 

1. Convert string to int, int to string.  Solution  
2. Find the next palindrome number.  Solution  
3. Print last N lines of file.  Solution  
4. Convert a string to equivalent number.  Solution  
5. Eight queen problem.  Solution 