https://leetcode.com/problems/x-of-a-kind-in-a-deck-of-cards/
https://leetcode.com/problems/length-of-last-word/
https://leetcode.com/problems/number-of-different-integers-in-a-string/
https://leetcode.com/problems/check-if-n-and-its-double-exist/
https://leetcode.com/problems/long-pressed-name/
https://leetcode.com/problems/valid-mountain-array/
https://leetcode.com/problems/can-place-flowers/
https://leetcode.com/problems/remove-one-element-to-make-the-array-strictly-increasing/
https://leetcode.com/problems/power-of-four/
https://leetcode.com/problems/partitioning-into-minimum-number-of-deci-binary-numbers/
https://leetcode.com/problems/deepest-leaves-sum/
https://leetcode.com/problems/merge-two-sorted-lists/