# | 제출 시각 | 아이디 | 문제 | 언어 | 결과 | 실행 시간 | 메모리 |
---|---|---|---|---|---|---|---|
509638 | socpite | NoM (RMI21_nom) | C++14 | 0 ms | 0 KiB |
이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
#include<bits/stdc++.h>
using namespace std;
#define f first
#define s second
const int maxn = 4e3+5;
const int mod = 1e9+7;
typedef long long ll;
int n, m;
ll dp[maxn][maxn][2];
int pos[maxn];
ll f(int i, int j, int k){
if(i == n)return k==0;
else if(dp[i][j][k] != -1)return dp[i][j][k];
else{
int gap = pos[i]-i;
dp[i][j][k] = 0;
int p2 = n/2 - j - (i-j)/2;
if(p2)dp[i][j][k]+=f(i+1, j+1, k)*p2*2%mod;
if(j)dp[i][j][k]+=f(i+1, j-1, k)*j%mod;
if(gap >= 2)dp[i][j][k]+=f(i+2, j, k^1)*p2*2%mod*(gap-1)%mod;
dp[i][j][k]%=mod;
//cout << i << " " << j << " " << k << " " << dp[i][j][k] << endl;
return dp[i][j][k];
}
}
int main(){
memset(dp, -1, sizeof(dp));
cin >> n >> m;
n*=2;
int crr = 0;
for(int i = 0; i < m-n%m; i++){
int st = crr+n/m;
for(int j = 0; j < n/m; j++)pos[crr++]=st;
}
for(int i = 0; i < n%m; i++){
int st = crr+n/m+1;
for(int j = 0; j < n/m+1; j++)pos[crr++]=st;
}
ll ans = f(0, 0, 0)- f(0, 0, 1);
if(ans < 0)ans+=mod;
cout << ans;
}
#include<bits/stdc++.h>
using namespace std;
#define f first
#define s second
const int maxn = 4e3+5;
const int mod = 1e9+7;
typedef long long ll;
int n, m;
ll dp[maxn][maxn][2];
int pos[maxn];
ll f(int i, int j, int k){
if(i == n)return k==0;
else if(dp[i][j][k] != -1)return dp[i][j][k];
else{
int gap = pos[i]-i;
dp[i][j][k] = 0;
int p2 = n/2 - j - (i-j)/2;
if(p2)dp[i][j][k]+=f(i+1, j+1, k)*p2*2%mod;
if(j)dp[i][j][k]+=f(i+1, j-1, k)*j%mod;
if(gap >= 2)dp[i][j][k]+=f(i+2, j, k^1)*p2*2%mod*(gap-1)%mod;
dp[i][j][k]%=mod;
//cout << i << " " << j << " " << k << " " << dp[i][j][k] << endl;
return dp[i][j][k];
}
}
int main(){
memset(dp, -1, sizeof(dp));
cin >> n >> m;
n*=2;
int crr = 0;
for(int i = 0; i < m-n%m; i++){
int st = crr+n/m;
for(int j = 0; j < n/m; j++)pos[crr++]=st;
}
for(int i = 0; i < n%m; i++){
int st = crr+n/m+1;
for(int j = 0; j < n/m+1; j++)pos[crr++]=st;
}
ll ans = f(0, 0, 0)- f(0, 0, 1);
if(ans < 0)ans+=mod;
cout << ans;
}