Next Permutation

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

Discuss

java code:

public void nextPermutation(int[] num)  
    {  
        if(num.length <= 1)  
            return ;  
        for(int i = num.length - 2; i >= 0; i--)  
        {  
            if(num[i] < num[i+1])  
            {  
                int j;  
                for(j = num.length - 1; j >= i; j--)  
                    if(num[i] < num[j])  
                        break;  
                // swap the two numbers.  
                num[i] = num[i] ^ num[j];  
                num[j] = num[i] ^ num[j];  
                num[i] = num[i] ^ num[j];  
                //sort the rest of arrays after the swap point.  
                Arrays.sort(num, i+1, num.length);  
                return ;  
            }  
        }  
        //reverse the arrays.  
        for(int i = 0; i < num.length / 2; i++)  
        {  
            int tmp = num[i];  
            num[i] = num[num.length - i - 1];  
            num[num.length - i - 1] = tmp;  
        }  
        return ;  
    }

补充：软件开发 , Java ,