Submission #1087978

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Source Code Expand

#include<vector>
#include<cmath>
#include<map>
#include<cstdlib>
#include<iostream>
#include<sstream>
#include<fstream>
#include<string>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<set>
#include<stack>
#include<bitset>
#include<functional>
#include<ctime>
#include<queue>
#include<deque>
#include<complex>
using namespace std;
#define pb push_back
#define pf push_front
typedef long long lint;
typedef complex<double> P;
#define mp make_pair
#define fi first
#define se second
typedef pair<int,int> pint;
#define All(s) s.begin(),s.end()
#define rAll(s) s.rbegin(),s.rend()
#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
lint dp[4545][2521][2];
int main()
{
	int N,M,K,x,y;cin>>N>>M>>K;
	x=(N+M-1);y=(K-1);
	memset(dp,0,sizeof(dp));
	dp[0][0][0]=1;
	lint out=0,mo=1000000007;
	rep(i,x/y) rep(j,M+1){
		if(i*y-j<0 || i*y-j>N-1) dp[i][j][0]=dp[i][j][1]=0;
		lint now=(dp[i][j][0]+dp[i][j][1])%mo;
		dp[i+1][j][0]+=now;dp[i][j][0]%=mo;
		REP(k,1,y+1){
			dp[i+1][j+k][1]+=now;
			dp[i+1][j+k][1]%=mo;
		}
	}
	rep(i,x/y+1) rep(j,M+1){
		if(i*y-j<0 || i*y-j>N-1) continue;
		if((M-j)%y>0) continue;
		//cout<<i<<' '<<j<<' '<<dp[i][j][0]<<' '<<dp[i][j][1]<<endl;
		out+=dp[i][j][1];out%=mo;
	}
	cout<<out%mo<<endl;
}

Submission Info

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