#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
int n,m,mod;
int p[30000010];
int pp[30000010];
inline int f(int x,int y)
{
return x*(m+1)+y;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int i,j;
cin>>n>>m>>mod;
p[f(0,m)]=pp[f(0,m)]=1;
for(i=1;i<=n;i++)
{
for(j=1;j<=m;j++)
{
long long tmp=(long long)j*(p[f(i-1,m)]-p[f(i-1,m-j)])-pp[f(i-1,j-1)];
p[f(i,j)]=(tmp+p[f(i,j-1)])%mod;
}
for(j=1;j<=m;j++)
pp[f(i,j)]=(pp[f(i,j-1)]+p[f(i,j)])%mod;
}
cout<<(p[f(n,m)]+mod)%mod<<"\n";
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | #include<bits/stdc++.h> #define fi first #define se second using namespace std; int n,m,mod; int p[30000010]; int pp[30000010]; inline int f(int x,int y) { return x*(m+1)+y; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); int i,j; cin>>n>>m>>mod; p[f(0,m)]=pp[f(0,m)]=1; for(i=1;i<=n;i++) { for(j=1;j<=m;j++) { long long tmp=(long long)j*(p[f(i-1,m)]-p[f(i-1,m-j)])-pp[f(i-1,j-1)]; p[f(i,j)]=(tmp+p[f(i,j-1)])%mod; } for(j=1;j<=m;j++) pp[f(i,j)]=(pp[f(i,j-1)]+p[f(i,j)])%mod; } cout<<(p[f(n,m)]+mod)%mod<<"\n"; return 0; } |
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