poj3187

#include <iostream>
#include <algorithm>
using namespace std;
int cnt[11][11];
int res[10];

inline int dot(int a[],int b[],int l){
int ret = 0;
for(int i=0;i<l;i++)ret = ret + a[i] * b[i];
return ret;
}
int main(int argc, const char * argv[]) {
cnt[1][0] = 1;
cnt[2][0] = cnt[2][1] = 1;
int i,j;
for(i=3;i<=10;i++){
cnt[i][0]=1;
for(j=1;j<i;j++){
cnt[i][j] = cnt[i-1][j]+cnt[i-1][j-1];
}
}
int N,sum;
cin>>N>>sum;
for(i=0;i<N;i++)res[i] = i+1;
do{
if(dot(res,cnt
,N)==sum)break;
}while(next_permutation(res, res+N));
for(i=0;i<N;i++)cout<<res[i]<<' ';
cout<<endl;
return 0;
}