# 16. 3Sum Closest (Medium)

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

Given an array `nums` of n integers and an integer `target`, find three integers in `nums` such that the sum is closest to `target`. Return the sum of the three integers. You may assume that each input would have exactly one solution.

Example:

```Given array nums = [-1, 2, 1, -4], and target = 1.

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

## Solutions

``````class Solution {

// Solution for Problem 15 is a good template. Memorize it as possible as you can.

public int threeSumClosest(int[] nums, int target) {
Arrays.sort(nums);

int ans = -1;
int min = Integer.MAX_VALUE;
for (int i = 0, l = nums.length; i < l - 2; i++) {

// nums[i - 1] is already calculated, skip nums[i] if same value with previous one
if (i != 0 && nums[i] == nums[i - 1]) {
continue;
}

int j = i + 1;
int k = l - 1;
while (j < k) {
if (j != i + 1 && (nums[j] == nums[j - 1])) {
j++;
continue;
}

// Since one exact solution only, stop searching to once found
int sum = nums[i] + nums[j] + nums[k];
if (sum == target) {
return sum;
}

// distance to target value, positive value
int dist = Math.abs(sum - target);
if (dist < min) {
min = dist;
ans = sum;
}

if (sum < target) {
j++; // approach target with larger value
}

if (sum > target) {
k--; // approach target with smaller value
}
}
}

return ans;
}
}
``````