https://leetcode.com/problems/implement-strstr/description/
https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
https://leetcode.com/problems/max-consecutive-ones/description/
https://leetcode.com/problems/merge-sorted-array/description/
https://leetcode.com/problems/nim-game/description/
https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/
https://leetcode.com/problems/reverse-integer/description/
https://leetcode.com/problems/roman-to-integer/description/
https://leetcode.com/problems/search-insert-position/description/
https://leetcode.com/problems/single-number-iii/description/
https://leetcode.com/problems/two-sum/description/
https://leetcode.com/problems/valid-parentheses/description/