深度搜索DFS

Permutation

Time Limit:1000ms   Memory Limit:65535KB

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Description

Selecting m of n integers to form permutations, in accordance with the order of increasing from left to right.
For example, m=3, n=5, the whole permutations are:
0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
1 2 3
1 2 4
1 3 4
2 3 4
the 3th permutation is 0 1 4

Input

Only one line with three integers: n, m, i
1<=n<=100, 1<=i<=10000

Output

One line contains the ith permutation

Sample Input

5 3 3

Sample Output

0 1 4

Hint

#include<iostream>
#include<cstring>
int m,n,ith,a[105],cc=0,find=0;
void dfs(int pre,int deep)
{//已有深度和层次
       if(find)
                   return;
     if(deep==m)
     { 
                cc++;
                if(cc==ith)
               {
                      for(int j=0;j<m;j++)
                                printf("%d ",a[j]);
                      printf("\n");
                      find=1;
                 }
                  return;
      }
      for(int i=pre+1;i<n;i++)
     {  
              a[deep]=i;
              dfs(i,deep+1);
              if(find)
               return;
      }
}
int main()
{
   scanf("%d%d%d",&n,&m,&ith);
   memset(a,0,sizeof(a));
   dfs(-1,0);
   return 0;
}