【记忆化搜索】bzoj3208 花神的秒题计划Ⅰ

暴力

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define N 701
const int dx[]={0,0,-1,1},dy[]={-1,1,0,0};
int n,mem[N][N],a[N][N],m;
bool cant[N][N];
int f(int x,int y)
{if(mem[x][y]) return mem[x][y];mem[x][y]=1;for(int i=0;i<4;++i)if(x+dx[i]>0&&x+dx[i]<=n&&y+dy[i]>0&&y+dy[i]<=n&&(!cant[x+dx[i]][y+dy[i]])&&a[x][y]>a[x+dx[i]][y+dy[i]])mem[x][y]=max(mem[x][y],f(x+dx[i],y+dy[i])+1);return mem[x][y];
}
int main()
{int A,B,C,D; char op[2];scanf("%d",&n);for(int i=1;i<=n;++i)for(int j=1;j<=n;++j)scanf("%d",&a[i][j]);scanf("%d",&m);for(;m;--m){scanf("%s",op);if(op[0]=='C'){scanf("%d%d%d",&A,&B,&C);a[A][B]=C;}else if(op[0]=='S'){scanf("%d%d%d%d",&A,&B,&C,&D);for(int i=A;i<=C;++i)for(int j=B;j<=D;++j)cant[i][j]=1;}else if(op[0]=='B'){scanf("%d%d%d%d",&A,&B,&C,&D);for(int i=A;i<=C;++i)for(int j=B;j<=D;++j)cant[i][j]=0;}else{int ans=1;memset(mem,0,sizeof(mem));for(int i=1;i<=n;++i)for(int j=1;j<=n;++j)if(!cant[i][j])ans=max(ans,f(i,j));printf("%d\n",ans);}}return 0;
}