LeetCode 16 3Sum Closest

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).

public int threeSumClosest(int[] nums, int target) {
Arrays.sort(nums);
int len = nums.length, flag = Integer.MAX_VALUE;
for (int i = 0; i < len - 2; i++) {
int left = i + 1, right = len - 1;
while (left < right) {
int sum = nums[i] + nums[left] + nums[right];
flag = Math.abs(sum - target) < Math.abs(flag) ? sum - target : flag;
if (sum < target) left++;//数据小,继续找后边大的数据.
else right--;//数据大,继续找前边小的数据.
}
}
return target + flag;
}