pku1088 dfs+dp记忆化搜索

#include <iostream>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>

const int inf = (1<<31)-1;
const int MAXN = 1e2+10;
using namespace std;

int dp[MAXN][MAXN];
int vist[MAXN][MAXN];
int a[MAXN][MAXN];
int n,m;

int mov[4][2]={-1,0,1,0,0,1,0,-1};

int check(int x,int y){
    if(x<1||y<1||x>n||y>m)return 0;
   // if(vist[x][y]==1)return 0;
    else return 1;
}

void dfs(int x,int y){
    int nx,ny;
   // cout<<"haha"<<endl;
    for(int i=0;i<4;i++){
        nx = x+mov[i][0];
        ny = y+mov[i][1];
        if(check(nx,ny)&&a[x][y]>a[nx][ny]){
            if(dp[nx][ny]==1){
               // vist[nx][ny] = 1;
                dfs(nx,ny);
                dp[x][y] = max(dp[x][y],dp[nx][ny]+1);
                //vist[nx][ny] = 0;
            }
            else{
                dp[x][y] = max(dp[x][y],dp[nx][ny]+1);
            }
        }
    }
}

int main()
{
    while(scanf("%d%d",&n,&m)!=EOF){
        int mmax = -inf;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                scanf("%d",&a[i][j]);
                dp[i][j] = 1;
                vist[i][j] = 0;
            }
        }
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                if(dp[i][j]!=1||vist[i][j]==0){
                    //if()
                    vist[i][j] = 1;
                    dfs(i,j);
                }
                mmax = max(mmax,dp[i][j]);
            }
        }
        /*for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                printf("%d ",dp[i][j]);
            }
            cout<<endl;
        }*/
        cout<<mmax<<endl;
    }
    //cout << "Hello world!" << endl;
    return 0;
}