[SHOI2002] Skiing

Template qwq for memoized search

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int R,C,map[101][101],ans,f[101][101],len;
int dx[4]={1,-1,0,0},
    dy[4]={0,0,-1,1};
int read(){
    int x=0,f=1;
    char c=getchar();
    while(c>'9'||c<'0'){
        if(c=='-')f=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9'){
        x=x*10+c-'0';
        c=getchar();
    }
    return x*f;
}
int dfs(int x,int y){
    if(f[x][y])return f[x][y];
    int l=1;
    for(int i=0;i<4;i++){
        int Nowx=x+dx[i];
        int Nowy=y+dy[i];
        if (Nowx>0&&Nowx<=R&&Nowy>0&&Nowy<=C&&map[x][y]>map[Nowx][Nowy])
            l=max(dfs(Nowx,Nowy)+1,l);
    }
    f[x][y]=l;
    return l;
    
}

int main(){
    R=read(),C=read();
    for(int i=1;i<=R;i++)
        for(int j=1;j<=C;j++)
            map[i][j]=read();
    for(int i=1;i<=R;i++)
        for(int j=1;j<=C;j++){
            len=dfs(i,j);
            f[i][j]=len;
            ans=max(f[i][j],ans);
        }
    printf("%d",ans);
    return 0;
}