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).

题目：给定一个数组S，找出S中的三个数，使其和与目标值最为接近。并返回其和。

	public int threeSumClosest(int[] num, int target) {
		int min = Integer.MAX_VALUE;
		int result = 0;
		Arrays.sort(num);
		for (int i = 0; i < num.length; i++) {
			int j = i + 1;
			int k = num.length - 1;
			while (j < k) {
				int sum = num[i] + num[j] + num[k];
				int minus = Math.abs(sum - target);
				if (minus == 0)
					return sum;
				if (minus < min) {
					min = minus;
					result = sum;
				}
				if (sum <= target)
					j++;
				else
					k--;
			}
		}
		return result;
	}

LeetCode——3Sum Closest