poj 3187 Backward Digit Sums

Description

    3   1   2   4

      4   3   6

        7   9

         16

Input

Output

Sample Input

4 16

Sample Output

3 1 2 4

Hint

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

int cont=0;
int n,i,a[15],vis[15],sum,bj=0;
void yz()
{
    int i,j,b[15];
    for(i=0;i<n;i++)
        b[i]=a[i];
    for(i=n-2;i>=0;i--)
        for(j=0;j<=i;j++)
    {
        b[j]+=b[j+1];
    }
    if(b[0]==sum)
        bj=1;
}


int main()
{
    int i;
    scanf("%d%d",&n,&sum);
    memset(vis,0,sizeof(vis));
    for(i=0;i<n;i++)
        a[i]=i+1;
    do
    {
        yz();
        if(bj==1)
        {
            for(i=0;i<n-1;i++)
                printf("%d ",a[i]);
            printf("%d\n",a[i]);
            break;
        }
    }
    while(next_permutation(a,a+n));


    return 0;

}