传送门
分析
提前预处理出来每一个联通块,然后去维护并查集即可
最后的答案是联通块数量的阶乘乘以每一个联通块的数量
代码
#pragma GCC optimize(3)
#include <bits/stdc++.h>
#define debug(x) cout<<#x<<":"<<x<<endl;
#define dl(x) printf("%lld\n",x);
#define di(x) printf("%d\n",x);
#define _CRT_SECURE_NO_WARNINGS
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef vector<int> VI;
const int INF = 0x3f3f3f3f;
const int N = 600;
const ll mod= 1000000007;
const double eps = 1e-9;
const double PI = acos(-1);
template<typename T>inline void read(T &a){
char c=getchar();T x=0,f=1;while(!isdigit(c)){
if(c=='-')f=-1;c=getchar();}
while(isdigit(c)){
x=(x<<1)+(x<<3)+c-'0';c=getchar();}a=f*x;}
int gcd(int a,int b){
return (b>0)?gcd(b,a%b):a;}
int dx[] = {
0,0,1,-1};
int dy[] = {
1,-1,0,0};
char g[N][N];
int num[N * N];
int st[N][N];
int idx,n,k;
ll fac[N * N];
int q[N * N];
int find(int x){
if(x != q[x])q[x] = find(q[x]);
return q[x];
}
ll ksm(ll x,ll y,ll z = mod){
ll ans=1,base=x;
while(y){
if(y&1)ans*=base,ans%=z;
base*=base;base%=z;
y>>=1;
}
return ans;
}
void dfs(int x,int y,int p){
st[x][y] = p;
num[p]++;
for(int i = 0;i < 4;i++){
int a = x + dx[i],b = y + dy[i];
if(a >= 1 && a <= n && b >= 1 && b <= n && !st[a][b] && g[a][b] == '1'){
dfs(a,b,p);
}
}
}
int main(){
read(n);fac[0] = 1;
for(int i = 1;i <= n * n;i++) {
q[i] = i;
fac[i] = (fac[i - 1] * i) % mod;
}
for(int i = 1;i <= n;i++) scanf("%s",g[i] + 1);
for(int i = 1;i <= n;i++)
for(int j = 1;j <= n;j++){
if(st[i][j]) continue;
if(g[i][j] == '0') continue;
dfs(i,j,++idx);
}
ll ans = fac[idx];
int l = idx;
for(int i = 1;i <= l;i++) ans = (ans * num[i]) % mod;
read(k);
while(k--){
int x,y;
read(x),read(y);
x++,y++;
if(g[x][y] == '1') {
dl(ans);
continue;
}
g[x][y] = '1';
int fa = -1;
for(int i = 0;i < 4;i++){
int a = x + dx[i],b = y + dy[i];
if(a < 1 || a > n || b < 1 || b > n || g[a][b] == '0') continue;
int fx = find(st[a][b]);
if(fa == -1){
st[x][y] = fx;
ans = (ans * ksm(num[fx],mod - 2)) % mod;
num[fx]++;
ans = (ans * num[fx]) % mod;
fa = fx;
}
else if(fa != fx){
q[fx] = fa;
ans = (ans * ksm(fac[idx],mod - 2)) % mod;
ans = (ans * ksm(num[fx],mod - 2)) % mod;
ans = (ans * ksm(num[fa],mod - 2)) % mod;
num[fa] += num[fx];
idx--;
ans = (ans * fac[idx]) % mod;
ans = (ans * num[fa]) % mod;
}
}
if(fa == -1){
st[x][y] = ++l;
num[l] = 1;
ans = (ans * ksm(fac[idx],mod - 2)) % mod;
idx++;
ans = (ans * fac[idx]) % mod;
}
dl(ans);
}
return 0;
}
/**
* ┏┓ ┏┓+ +
* ┏┛┻━━━┛┻┓ + +
* ┃ ┃
* ┃ ━ ┃ ++ + + +
* ████━████+
* ◥██◤ ◥██◤ +
* ┃ ┻ ┃
* ┃ ┃ + +
* ┗━┓ ┏━┛
* ┃ ┃ + + + +Code is far away from
* ┃ ┃ + bug with the animal protecting
* ┃ ┗━━━┓ 神兽保佑,代码无bug
* ┃ ┣┓
* ┃ ┏┛
* ┗┓┓┏━┳┓┏┛ + + + +
* ┃┫┫ ┃┫┫
* ┗┻┛ ┗┻┛+ + + +
*/