首页 > 代码库 > 3Sum Closest

3Sum Closest

题目

Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution.

    For example, given array S = {-1 2 1 -4}, and target = 1.

    The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).

方法

思路和上一题一样。
    public int threeSumClosest(int[] num, int target) {
        Arrays.sort(num);
        int len = num.length;
        int min = num[0] + num[1] + num[2];
        for (int i = 0; i < len - 2; i++) {
            int left = i + 1;
            int right = len - 1;
            while (left < right) {
                int temp = num[left] + num[right] + num[i];
                if (Math.abs(min - target) > Math.abs(temp - target)) {
                    min = temp;
                }
                if (temp == target) {
                    return target;
                } else if (temp > target){
                    right--;
                } else {
                    left++;
                }
            }
        }
        return min;
    }