記憶化搜尋

暴力模擬即可

每次保護或撤銷或改變海拔就暴力修改，然後對於詢問，記憶化搜尋一下就好了

程式碼

//By AcerMo
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int M=1050;
int n,m;
int a[M][M],f[M][M],vis[M][M];
int fx[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
inline
 
 void read(int &x)
{
	x=0;char ch=getchar();
	while (!isdigit(ch)) ch=getchar();
	while (isdigit(ch)) x=x*10+ch-'0',ch=getchar();
	return ;
}
inline void flag(int x,int y,int z,int g,bool f)
{
	for (int i=x;i<=z;i++)
	for (int k=y;k<=g;k++)
	vis[i][k]=f;
	return ;
}
inline int find(int x,int y)
 

{
	if (vis[x][y]) return -2e9;
	if (f[x][y]!=-1) return f[x][y];
	f[x][y]=1;
	for (int i=0;i<4;i++)
	{
		int nx=x+fx[i][0];
		int ny=y+fx[i][1];
		if (nx<1||nx>n||ny<1||ny>n) continue;
		if (a[x][y]>a[nx][ny]) 
		f[x][y]=max(f[x][y],find(nx,ny)+1);
	}
	return f[x][y];
}
signed main(
 
)
{
	read(n);
	for (int i=1;i<=n;i++)
	for (int k=1;k<=n;k++)
	read(a[i][k]);
	read(m);int x,y,z,g;
	while (m--)
	{
		char c;cin>>c;
		if (c=='Q')
		{
			memset(f,-1,sizeof(f));
			int ans=0;
			for (int i=1;i<=n;i++)
			for (int k=1;k<=n;k++)
			ans=max(ans,find(i,k));
			printf("%d\n",ans);
			continue;
		}
		read(x),read(y),read(z);
		if (c=='C'){a[x][y]=z;continue;}
		read(g);
		if (c=='B') flag(x,y,z,g,0);
		if (c=='S') flag(x,y,z,g,1);
	}
	return 0; 
}