# 3Sum Closest – Leetcode Solution

In this post, we are going to solve the 16. 3Sum Closest problem of Leetcode. This problem 16. 3Sum Closest is a Leetcode medium level problem. Let’s see code, 16. 3Sum Closest.

## Problem

Given an integer array `nums` of length `n` 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 1 :

``````
Input: nums = [-1,2,1,-4], target = 1
Output: 2
Explanation: The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
``````

### Example 2 :

``````
Input: nums = [0,0,0], target = 1
Output: 0
Explanation: The sum that is closest to the target is 0. (0 + 0 + 0 = 0).
``````

### Constraints

• `3 <= nums.length <= 500`
• `-1000 <= nums[i] <= 1000`
• `-104 <= target <= 104`

Now, let’s see the code of 16. 3Sum Closest – Leetcode Solution.

# 3Sum Closest – Leetcode Solution

### 16. 3Sum Closest – Solution in Java

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

for (int i = 0; i < nums.length; i++) {
int left = i + 1;
int right = nums.length - 1;

while (left < right) {
int sum  = nums[i] + nums[left] + nums[right];

if (Math.abs(target - sum) < Math.abs(diff)) {
diff = target - sum;
}

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

### 16. 3Sum Closest – Solution in C++

```class Solution {
public:
int threeSumClosest(vector<int>& nums, int target) {
sort(nums.begin(), nums.end());
int n = nums.size(), ans = nums + nums + nums;
for (int i = 0; i < n-2; ++i) {
int l = i + 1, r = n - 1;
while (l < r) {
int sum3 = nums[i] + nums[l] + nums[r];
if (abs(ans - target) > abs(sum3 - target))
ans = sum3;
if (sum3 == target) break;
if (sum3 > target)
--r;
else
++l;
}
}
return ans;
}
};```

### 16. 3Sum Closest– Solution in Python

```class Solution:
def threeSumClosest(self, nums: List[int], target: int) -> int:
nums.sort()
n = len(nums)
ans = nums + nums + nums
for i in range(n-2):
l, r = i + 1, n - 1
while l < r:
sum3 = nums[i] + nums[l] + nums[r]
if abs(ans - target) > abs(sum3 - target):
ans = sum3
if sum3 == target: return target
if sum3 > target:
r -= 1
else:
l += 1
return ans```

Note: This problem 16. 3Sum Closest is generated by Leetcode but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.