LeetCode题解——3Sum Closest

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).

class Solution {
public:
int threeSumClosest(vector<int>& nums, int target) {
int ans = nums[0]+nums[1]+nums[2];
int sum;
sort(nums.begin(),nums.end());
for(int i=0; i<nums.size()-1;i++)
{
int lo = i+1;
int hi = nums.size()-1;
while(lo<hi)
{
sum = nums[lo]+nums[hi]+nums[i];
if(sum==target)
return target;
else if(sum>target) {
ans=(sum-target)>abs(ans-target)?ans:sum;
hi--;
}
else{
ans=-(sum-target)>abs(ans-target)?ans:sum;
lo++;
}
}
}
return ans;
}
};

只要理解了前一道3sum的题，这道题就迎刃而解[/code]