| Input array is sorted |
Binary Search |
|
2 Pointers |
|
|
| all Permutations and subsets are asked |
Backtracking |
|
|
| given a Tree/ Graph |
DFS ,BFS |
|
|
| given a linked list |
2 Pointers |
|
|
| recursion is banned |
Stack |
|
|
| Must solve in-place |
Swap coressponding values |
|
Store One or more diffirent values in same pointer. |
|
|
| asked for maximum/minimum subarray/subset/options |
Dynamic Programming |
|
|
| asked for top/least K items |
Heap |
|
|
| asked for common strings |
Map ,Trie |
|
Else |
|
Map/Set for o(1) time and o(n) space |
|
Sort input for O(nlogn) time o(1) space |
