Submission #1995154

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;

const int MX=4015,md=1000000007;

int n,m,k,f[MX][MX],s[MX];
int main(){
	int i,j;
	cin>>n>>m>>k;
	f[0][0]=1;
	for(i=1;i<n+m;i++){
		memcpy(s,f[i-1],sizeof(int)*(m+1));
		for(j=1;j<=m;j++)s[j]=(s[j-1]+s[j])%md;
		for(j=0;j<=m;j++)f[i][j]=(s[j]+md-(j>=k?s[j-k]:0))%md;
	}
	int ans=0;
	while(m>0){
		ans=(ans+f[(n+m-1)/(k-1)][m])%md;
		m-=k-1;
	}
	cout<<ans<<endl;
	return 0;
}

Submission Info

Judge Result