| 0155-min-stack |
| 0020-valid-parentheses |
| 0844-backspace-string-compare |
| 1544-make-the-string-great |
| 0921-minimum-add-to-make-parentheses-valid |
| 0001-two-sum |
| 0242-valid-anagram |
| 2215-find-the-difference-of-two-arrays |
| 0496-next-greater-element-I |
| 0268-missing-number |
| 0206-reverse-linked-list |
| 0876-middle-of-the-linked-list |
| 0141-linked-list-cycle |
| 0019-remove-nth-node-from-end-of-list |
| 0021-merge-two-sorted-lists |