POJ 1088 滑雪（记忆化搜索）

#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<sstream>
#include<cstring>
#include<bitset>
#include<string>
#include<deque>
#include<stack>
#include<cmath>
#include<queue>
#include<set>
#include<map>
using namespace std;
#define INF 0x3f3f3f3f
#define CLR(x,y) memset(x,y,sizeof(x))
#define LC(x) (x<<1)
#define RC(x) ((x<<1)+1)
#define MID(x,y) ((x+y)>>1)
typedef pair<int,int> pii;
typedef long long LL;
const double PI=acos(-1.0);
const int N=110;
int pos[N][N],direct[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
int dp[N][N];
int n,m;
int dfs(int x,int y)
{
    if(dp[x][y])
        return dp[x][y];
    else
    {
        int maxm=0;
        for (int i=0; i<4; ++i)
        {
            int xx=x+direct[i][0];
            int yy=y+direct[i][1];
            if(xx>=0&&xx<n&&yy>=0&&yy<m&&pos[xx][yy]<pos[x][y])
                maxm=max<int>(maxm,dfs(xx,yy));
        }
        return dp[x][y]=maxm+1;
    }
}
int main(void)
{
    int i,j;
    while (~scanf("%d%d",&n,&m))
    {
        CLR(dp,0);

        for (i=0; i<n; ++i)
            for (j=0; j<m; ++j)
                scanf("%d",&pos[i][j]);
                
        for (i=0; i<n; ++i)
            for (j=0; j<m; ++j)
                dfs(i,j);
                
        int ans=1;
        for (i=0; i<n; ++i)
            for (j=0; j<m; ++j)
                if(dp[i][j]>ans)
                    ans=dp[i][j];
                    
        printf("%d\n",ans);
    }
    return 0;
}