[LeetCode]Next Permutation

标签：java   leetcode   

Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.

If such arrangement is not possible, it must rearrange it as the lowest possible order (ie, sorted in ascending order).

The replacement must be in-place, do not allocate extra memory.

Here are some examples. Inputs are in the left-hand column and its corresponding outputs are in the right-hand column.
1,2,3 → 1,3,2
3,2,1 → 1,2,3
1,1,5 → 1,5,1

public class Solution {
	public void nextPermutation(int[] num) {
		int len = num.length;
		int k = 0;
		for (int i = len - 1; i > 0; i--) {
			if (num[i] > num[i - 1]) {
				k = i;
				break;
			}
		}
		if (k == 0) {
			Arrays.sort(num);
			return;
		}
		for (int i = len - 1; i >= k; i--) {
			if (num[k - 1] < num[i]) {
				num[k - 1] = num[k - 1] ^ num[i];
				num[i] = num[k - 1] ^ num[i];
				num[k - 1] = num[k - 1] ^ num[i];
				break;
			}
		}
		Arrays.sort(num, k, len);
		return;
	}
}

[LeetCode]Next Permutation

标签：java   leetcode   

原文地址：http://blog.csdn.net/guorudi/article/details/39235823