next permutation 

 1 class Solution {
 2 public:
 3     void nextPermutation(vector<int> &num) {
 4         // Start typing your C/C++ solution below
 5         // DO NOT write int main() function
 6         if( num.size() == 1 ) return;
 7         int pos = -1;
 8         for(int i = num.size() - 1; i>=1; i-- )
 9             if( num[i] > num[i-1] )
10             {
11                 pos = i-1;
12                 break;
13             }  
14         if( pos == -1 )
15         {
16             sort(num.begin(),num.end() );
17             return;
18         } 
19         int top = INT_MAX;
20         int top_pos = -1;
21         for(int i = num.size() - 1; i>pos; i--)
22         {
23             if( num[i] > num[pos] && num[i] < top)
24             {
25                 top_pos = i;
26                 top = num[i];
27                 break;
28             }               
29         }
30         
31         num[top_pos] = num[pos];
32         num[pos] = top;
33         sort(num.begin() + pos + 1, num.end() );
34         return;
35         
36     }
37 };

 

posted on 2013-09-04 19:16  jumping_grass  阅读(143)  评论(0)    收藏  举报

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