Published onMarch 31, 2022[LeetCode 138] Copy List with Random PointerLinkedListrandom pointer, which could point to any node in the list, or `null`.
Published onMarch 28, 2022[LeetCode 130] Surrounded RegionsGraphGiven an `m x n` matrix `board` containing `'X'` and `'O'`, capture all regions that are 4-directionally surrounded by 'X'.