package ThreeSumClosest;

import java.util.Arrays;

/**

* User: Danyang

* Date: 1/17/2015

* Time: 13:10

*

* 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 {

/**

* Two Pointers

*

* @param num

* @return

*/

public int threeSumClosest(int[] num, int target) {

Arrays.sort(num);

int n = num.length;

int sum_min = num[0]+num[1]+num[2];

for(int i=0; i<n-2; ) {

int j = i+1;

int k = n-1;

while(j<k) {

int sum = num[i]+num[j]+num[k];

if(Math.abs(sum_min-target)>Math.abs(sum-target))

sum_min = sum;

if(sum==target) {

return target;

}

else if(sum>target)

k--;

else

j++;

}

i++;

while(i<n-2 && num[i]==num[i-1])

i++;

}

return sum_min;

}

}