Tencent 小Q的歌单

#include <cstdio>
#include <iostream>
using namespace std;
 
long long c[105][105];
const int mod = 1000000007;
void init()
{     
    c[0][0]=1;     
    for(int i=1;i<=100;i++)
    {         
        c[i][0]=1;         
        for(int j=1;j<=100;j++)
        {            
            c[i][j] = (c[i-1][j-1]+c[i-1][j])%mod;         
        }    
    } 
}

int main()
{     
    int k,x,y,a,b;     
    long long sum = 0;
    init();     
    cin>>k>>a>>x>>b>>y;
    int i, j;
    for(i=0;i<=x;i++)
    {                 
        for(j=0;j<=y;j++)
        {                    
            if((i*a+j*b)>k)                        
                break;                     
            if((i*a+j*b)==k)
            {                        
                sum+=c[x][i]*c[y][j];                     
            }                 
        }             
    }                
    printf("%ld\n",sum%1000000007);     
  
    return 0;
 }