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).
public class Solution {
public int threeSumClosest(int[] num, int target) {
int sum = 0, length = num.length;
if(length > 0) {
if(length <= 3) {
for(int i = 0; i < length; ++i)
sum += num[i];
}
else {
Arrays.sort(num);
int difference = Integer.MAX_VALUE;
for(int i = 0; i < length; ++i) {
int start = i + 1, end = length - 1;
while(start < end){
int temp = num[i] + num[start] + num[end];
if(temp == target)
return target;
else {
if(difference > Math.abs((target - temp))){
sum = temp;
difference = Math.abs((target - temp));
}
if(temp < target)
++start;
else
--end;
}
}
}
}
}
return sum;
}
}
leetcode--3Sum Closest,布布扣,bubuko.com
原文：http://www.cnblogs.com/averillzheng/p/3806313.html