Beginner ACM-Combinatorial Mathematics basic topic PKU 1833

Title Link: http://poj.org/problem?id=1833

Test instructions is very clear, is to find out the current arrangement of the first K-permutation.

Easily, you can use the STL's Next_permulation () function to write an answer:

#include  <iostream> #include  <cstdio> #include  <algorithm>using namespace  std;int data[1025];int main () {    int n,k,m;     scanf ("%d", &m);     while (m--)     {      &NBSP;&NBSP;&NBSP;SCANF ("%d%d", &n,&k);         for (int i=0 ;  i<n; i++)         {       &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SCANF ("%d", &data[i]);         }         while (k--)              next_permutation (data,data+n);         for (int  i=0; i<n; i++)         {             printf ("%d ", Data[i]);        }         putchar (' \ n ');    }     return 0;}

However submitted, will prompt timeout ...

Some can not touch the mind, because the online AC code is basically also called K-times next_permulation write.

And then saw this article:Poj 1833 arrangement--a messy water problem

Only to understand that the original number of calls to the printf function also times out:

So, just copy it to the output buffer at once.

#include  <iostream> #include  <cstdio> #include  <iterator> #include  < Algorithm>using namespace std;int data[1025];int main () {    int &NBSP;N,K,M;&NBSP;&NBSP;&NBSP;&NBSP;SCANF ("%d", &m);     while (m--)     &NBSP;{&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SCANF ("%d%d", &n,&k);         for (int i=0; i<n; i++)         &NBSP;{&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;SCANF ("%d", &data[i]);         }        while (k--)              next_permutation (data,data+n);         copy (data,data+n-1,ostream_iterator<int> (cout, " "));         cout<<data[n-1]<<endl;    }    return 0;} 

At this point AC, only 500ms, indicating that the call to printf at least 500ms of time consumed. But the same code, the use of C + + mode of submission ran 985ms, almost the line ran out.

Run ID User problem Result Memory time Language Code Length Submit time

14813838 Arclabs001 1833 Accepted 696K 500MS g++ /c14>477b 2015-10-14 17:41:22

14813836 Arclabs001 1833 Accepted 204K 985MS C + + 477B 2015-10-14 17:40:55

Beginner ACM-Combinatorial Mathematics basic topic PKU 1833