Title
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).
三数和最接近
Solution
类似三数和问题，使用双指针 O(n2)解决
//cpp:
class Solution {
public:
int threeSumClosest(vector<int>& nums, int target) {
int ans = nums[0]+nums[1]+nums[2];
sort(nums.begin(),nums.end());
for (int i = 0; i < nums.size(); i++) {
int lo = i+1, hi = nums.size() - 1;
while (lo < hi) {
int sum = nums[i] + nums[lo] + nums[hi];
if (sum > target)
hi--;
else
lo++;
ans = abs(sum - target) < abs(ans - target) ? sum : ans;
//cout<<ans<<endl;
}
}
return ans;
}
};