lintcode 中等题：next permutation下一个排列

class Solution:
    # @param num :  a list of integer
    # @return : a list of integer
    def nextPermutation(self, nums):
        # write your code here
        peakInd = len(nums) - 1
        while peakInd>0 and nums[peakInd] <= nums[peakInd-1]:
            peakInd -=1
        peakInd -=1
        if peakInd>=0:
            swapInd = peakInd + 1
            while swapInd< len(nums) and nums[swapInd]> nums[peakInd]:
                swapInd +=1
            swapInd -=1
            nums[swapInd],nums[peakInd] = nums[peakInd],nums[swapInd]
        left = peakInd + 1
        right = len(nums) - 1
        while left < right:
            nums[left],nums[right] = nums[right],nums[left]
            left +=1
            right -=1
        return nums

public class Solution {
    /**
     * @param nums: an array of integers
     * @return: return nothing (void), do not return anything, modify nums in-place instead
     */
    public int[] nextPermutation(int[] nums) {
        // write your code here
        int peakInd = nums.length-1;
        while(peakInd>0 && nums[peakInd-1] >= nums[peakInd]){
            peakInd --;
        }
        peakInd --;
        if(peakInd>=0){
            int swapInd = peakInd + 1;
            while(swapInd< nums.length && nums[swapInd] > nums[peakInd]){
                swapInd ++;
            }
            swapInd --;
            swapnums(nums,peakInd,swapInd);
        }
        int left = peakInd + 1;
        int right = nums.length - 1;
        while(left< right){
            swapnums(nums,left,right);
            left +=1;
            right -=1;
        }
        
        return nums;
    }
    private void swapnums(int[] nums,int left,int right){
            int tmp = nums[left];
            nums[left] = nums[right];
            nums[right] = tmp;
        }
}