3428. 放苹果

思路：dfs

代码：

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

int n, m;

int dfs(int u, int sum, int last){
    
    
    if(u == n){
    
        if (sum == 0) return 1;
        return 0;
    }
    
    int res = 0;
    
    for(int i = last; i <= sum; i++)
        res += dfs(u+1, sum - i , i);
        
    return res;
}
int main()
{
    
    
    while(cin >> m >> n)
        cout << dfs(0, m, 0) << endl;
        
        
    
    return 0;
}