[leetcode] 3Sum smaller

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

public class Solution { public int threeSumSmaller(int[] nums, int target) { if (nums == null || nums.length == 0) return 0; Arrays.sort(nums); int total = 0; for (int i = 0; i < nums.length-1; i++){ total += twoSumSmaller(nums, i+1, target-nums[i]); } return total; } public int twoSumSmaller(int []nums, int start, int target){ int total = 0; int left = start; int right = nums.length-1; while (left < right){ if (nums[left]+nums[right] < target){ total+=(right-left); left++; }else{ right--; } } return total; } }