LeetCode-in-Java
16. 3Sum Closest
Medium
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
Constraints:
3 <= nums.length <= 1000-1000 <= nums[i] <= 1000-104 <= target <= 104
Solution
import java.util.Arrays;
public class Solution {
public int threeSumClosest(int[] nums, int target) {
if (nums == null || nums.length < 3) {
return 0;
}
if (nums.length == 3) {
return nums[0] + nums[1] + nums[2];
}
Arrays.sort(nums);
int n = nums.length;
int sum = nums[0] + nums[1] + nums[2];
for (int i = 0; i < n - 2; i++) {
if (nums[i] + nums[n - 1] + nums[n - 2] < target) {
sum = nums[i] + nums[n - 1] + nums[n - 2];
continue;
}
if (nums[i] + nums[i + 1] + nums[i + 2] > target) {
int temp = nums[i] + nums[i + 1] + nums[i + 2];
return lessGap(sum, temp, target);
}
int j = i + 1;
int k = n - 1;
while (j < k) {
int temp = nums[i] + nums[j] + nums[k];
if (temp == target) {
return target;
}
if (temp < target) {
j++;
} else {
k--;
}
sum = lessGap(sum, temp, target);
}
}
return sum;
}
private int lessGap(int sum, int temp, int target) {
return Math.abs(sum - target) < Math.abs(temp - target) ? sum : temp;
}
}