[leetcode]3Sum Closest

新博文地址[leetcode]3Sum Closest

http://oj.leetcode.com/problems/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).

 跟3Sum那道题目类似，就不罗嗦了，我想尝试用不一样的算法求解。。。今天状态实在是糟糕，没想到，姑且依葫芦画瓢吧

 public int threeSumClosest(int[] num, int target) {
		mergeSort(num, 0, num.length - 1);
		int min = Math.abs(num[0] + num[1] + num[2] - target);
		if (num.length == 3) {
			return num[0] + num[1] + num[2];
		}
		int result = 0; 
		for (int i = 0; i <= num.length - 3; i++) {
			int a = i, b = i + 1, c = num.length - 1;
			while (b < c) {
				if (num[a] + num[b] + num[c] - target > 0) {
					if (Math.abs(num[a] + num[b] + num[c] - target) <= min) {
						min = Math.abs(num[a] + num[b] + num[c] - target);
						result = num[a] + num[b] + num[c];
					}
					c--;
				} else {
					if (Math.abs(num[a] + num[b] + num[c] - target) <= min) {
						min = Math.abs(num[a] + num[b] + num[c] - target);
						result = num[a] + num[b] + num[c];
					}
					b++;
				}
			}
		}
		return result;
	
    }