16. 最接近的三数之和

双指针

import java.util.Arrays;

class Solution {
    public int threeSumClosest(int[] nums, int target) {

        /**
         * 类似于《15. 三数之和》
         */
        int min = Integer.MAX_VALUE;
        int res = 0;
        Arrays.sort(nums);

        for (int i = 0; i <= nums.length - 3; i++) {

            if (i > 0 && nums[i] == nums[i - 1]){
                continue;
            }

            int left = i + 1;
            int right = nums.length - 1;

            while (left < right) {

                int sum = nums[i] + nums[left] + nums[right];
                int abs = Math.abs(sum - target);

                if (abs < min) {

                    min = abs;
                    res = sum;
                }

                if (sum > target) {
                    right--;
                } else if (sum < target) {
                    left++;
                } else {
                    return sum;
                }
            }
        }

        return res;
    }
}

/**
 * 时间复杂度 O(n^2)
 * 空间复杂度 O(1)
 */

https://leetcode-cn.com/problems/3sum-closest/

posted @ 2021-12-07 16:16  振袖秋枫问红叶  阅读(36)  评论(0)    收藏  举报