题意：有n个人写m行代码，第i个人写一行代码会产生ai个bug，问bug小于b的方案数

思路：背包二维费用

AC代码：

#include "iostream"#include "string.h"#include "stack"#include "queue"#include "string"#include "vector"#include "set"#include "map"#include "algorithm"#include "stdio.h"#include "math.h"#define ll long long#define bug(x) cout<
     
      <<" "<<"UUUUU"<
      
       >n>>m>>b>>mod;    for(int i=1; i<=n; ++i){        cin>>a[i];    }    for(int i=1; i<=n; ++i)        for(int k=1; k<=m; ++k){            for(int j=a[i]; j<=b; ++j){                dp[k][j]=dp[k-1][j-a[i]]+dp[k][j];                dp[k][j]%=mod;            }    }    ll ans=0;    for(int i=0; i<=b; ++i){        ans+=dp[m][i];        ans%=mod;    }    cout<<(ans+mod)%mod<