1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
class Solution {
public int threeSumClosest(int[] nums, int target) {
Arrays.sort(nums);
int ans = Integer.MAX_VALUE;
for (int i = 0; i < nums.length - 2; i++) {
int left = i + 1, right = nums.length - 1;
while (left < right) {
int currSum = nums[i] + nums[left] + nums[right];
if (Math.abs(currSum - target) < Math.abs(ans - target)) {
ans = currSum;
}
if (currSum < target) {
left += 1;
} else if (currSum > target) {
right -= 1;
} else {
return currSum;
}
}
}
return ans;
}
}

是3Sum的变种.

时间复杂度: O(n^2)
空间复杂度: O(nlogn) sort需要用栈.