This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
#define ll long long
#define maxn 55
#define mod 1000000007
using namespace std;
ll gt[10000];
int a[maxn][maxn],n,r,c;
ll f[maxn][maxn][maxn][maxn];
int topx,topy,downx,downy;
template<typename T> inline void read(T &x)
{
char c;
bool neg = false;
while (!isdigit(c = getchar()) && c != '-');
x = 0;
if (c == '-')
{
neg = true;
c = getchar();
}
do
{
x = x * 10 + c - '0';
}
while (isdigit(c = getchar()));
if (neg) x = -x;
}
template<typename T> inline void write(T x)
{
if (x < 0)
{
putchar('-');
write(-x);
return;
}
if (x < 10)
{
putchar(char(x + 48));
}
else
{
write(x/10);
putchar(char(48 + x%10));
}
}
template<typename T> inline void writeln(T x)
{
write(x);
putchar('\n');
}
ll tinh(int Ux,int Uy,int Vx,int Vy)
{
ll res=0;
if (Ux==1&&Uy==1&&Vx==r&&Vy==c) return 1;
if (f[Ux][Uy][Vx][Vy]!=-1) return f[Ux][Uy][Vx][Vy];
if (Ux>1)
{
res=(res+(1ll*gt[Vy-Uy+1]*tinh(Ux-1,Uy,Vx,Vy))%mod)%mod;
}
if (Vx<r)
{
res=(res+(1ll*gt[Vy-Uy+1]*tinh(Ux,Uy,Vx+1,Vy))%mod)%mod;
}
if (Uy>1)
{
res=(res+(1ll*gt[Vx-Ux+1]*tinh(Ux,Uy-1,Vx,Vy))%mod)%mod;
}
if (Vy<c)
{
res=(res+(1ll*gt[Vx-Ux+1]*tinh(Ux,Uy,Vx,Vy+1))%mod)%mod;
}
f[Ux][Uy][Vx][Vy]=res;
return res;
}
int main()
{
//freopen("Mascots.inp","r",stdin);
cin.tie(0);
cout.tie(0);
read(r);
read(c);
read(n);
topx=1e9,topy=1e9;
for (int i=1; i<=n; ++i)
{
int u,v;
read(u);
read(v);
topx=min(topx,u);
topy=min(topy,v);
downx=max(downx,u);
downy=max(downy,v);
a[u][v]=1;
}
gt[0]=1;
for (int i=1;i<=r*c;++i)
gt[i]=(gt[i-1]*i)%mod;
int d=0;
for (int i=topx;i<=downx;++i)
for (int j=topy;j<=downy;++j)
if (a[i][j]==0) ++d;
memset(f,-1,sizeof f);
cout<<(1ll*tinh(topx,topy,downx,downy)*gt[d])%mod;
}
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