记忆化搜索 | 洛谷 | P1434

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https://www.luogu.org/problemnew/show/P1434

#include <bits/stdc++.h>
#define FF(a,b) for(int a=0;a<b;a++)
#define F(a,b) for(int a=1;a<=b;a++)
#define LEN 110
#define bug(x) cout<<#x<<"="<<x<<endl;

using namespace std;

int g[LEN][LEN];
int res[LEN][LEN];
int vis[LEN][LEN];
int N,M;
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};

int valid(int i,int b){
    if(i>=0 && i<b)
        return 1;
    return 0;
}

int dfs(int x,int y){
    if(res[x][y]) return res[x][y];
    int ans=0;
    vis[x][y]=1;
    FF(i,4){
        int cx=x+dx[i];
        int cy=y+dy[i];
        if(valid(cx,N) && valid(cy,M) && (!vis[cx][cy]) && g[cx][cy]<g[x][y] )
            ans=max(ans,dfs(cx,cy)+1);
    }
    vis[x][y]=0;
    res[x][y]=ans;
    return ans;
}

int main()
{
    freopen("./in","r",stdin);
    scanf("%d%d",&N,&M);
    FF(i,N)FF(j,M)scanf("%d",&g[i][j]);
    int ans=0;
    FF(i,N)FF(j,M)ans=max(ans,dfs(i,j));
    printf("%d",ans+1);
    return 0;
}