[LeetCode] 14. Longest Common Prefix
[LeetCode] 20. Valid Parentheses
[LeetCode] 21. Merge Two Sorted Lists
26. Remove Duplicates from Sorted Array
[LeetCode] 27. Remove Element
[LeetCode] 28. Implement strStr()
[LeetCode] 35. Search Insert Position
[LeetCode] 66. Plus One
[LeetCode] 88. Merge Sorted Array
111. Minimum Depth of Binary Tree