LeetCode -- 3SumCloset

Question:

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).

Analysis:

与3Sum题目比较起来，这里不需要去重检测，只需要有两个变量控制sum和与target间的差距即可。总体的策略同3Sum。

Answer：

public class Solution {
public int threeSumClosest(int[] nums, int target) {
int tar = Integer.MAX_VALUE;
int res = 0;
Arrays.sort(nums);

for(int i=0; i<nums.length-2; i++) {
int j = i + 1;
int k = nums.length - 1;

while(j < k) {
int sum = nums[i] + nums[j] + nums[k];
if(sum == target)
return sum;
else {
int dif = Math.abs(sum - target);
if(dif < tar) {
tar = dif;
res = sum;
}
if(sum < target)
j++;
else
k--;
}
}
}
return res;
}
}