【小熊刷题】3Sum Closest <Leetcode 16, Java>

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).

*Difficulty: Medium

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

Solution

跟之前3Sum的很像，也是用two pointer的方法

public class Solution {
public int threeSumClosest(int[] nums, int target) {
int close = 0;
if(nums.length < 3){
for(int i : nums) close += i;
return close;
}else{
close = nums[0]+nums[1]+nums[2];
}
Arrays.sort(nums);
for(int i = 0; i < nums.length-2; i++){
int a = nums[i];
int start = i+1;
int end = nums.length-1;
while(start < end){
int b = nums[start];
int c = nums[end];
int currSum = a+b+c;
if(Math.abs(target - currSum) < Math.abs(target-close)) {
close = currSum;
}
if(currSum == target) return target;
else if(currSum > target) end--;
else start++;
}
}
return close;

}
}