| 1 | Sort Characters by frequency |    | | |
| 2 | Maximum Nesting Depth of Paranthesis |   | | |
| 3 | Roman Number to Integer and vice versa |    | | |
| 4 | Implement Atoi |    | | |
| 5 | Count Number of Substrings |   | | |
| 6 | Longest Palindromic Substring[Do it without DP] |   | | |
| 7 | Sum of Beauty of all substring |    | | |
| 8 | Reverse Every Word in A String |    | | |