242.有效的字母异位词 create Arraylist to store String，比较里面的element，s++，i--，判断条件，...

class Solution { public ListNode swapPairs(ListNode head) { if (he...

203.Remove Linked List Elements class Solution { public ListNode remov...

977.有序数组的平方 class Solution { public int[] sortedSquares(int[] nums) { ...

704.Binary Search class Solution { public int search(int[] nums, int t...