【洛谷1434 [SHOI2002]滑雪】记忆化搜索

AC代码

#include <bits/stdc++.h>

using namespace std;

#define ms(a,b) memset(a,b,sizeof(a))

typedef long long ll;

const int dx[4]={1,0,-1,0};
const int dy[4]={0,1,0,-1};

int vis[105][105], a[105][105];
int r, c;
int f[105][105];

inline int read()
{
    int X=0,w=0; char ch=0;
    while(!isdigit(ch))
    {
        w|=ch=='-';
        ch=getchar();
    }
    while(isdigit(ch))
    {
        X=(X<<3)+(X<<1)+(ch^48);
        ch=getchar();
    }
    return w?-X:X;
}

int dfs( int x, int y ) 
{
    if ( f[x][y] ) return f[x][y] ;
    int tmp=1;
    for (int i= 0; i < 4; i++) 
    {
        int nx = x + dx[i], ny = y + dy[i];
        if (nx<1 || nx>r || ny<1 || ny>c) continue;
        if (a[x][y] < a[nx][ny] ) tmp = max( dfs( nx, ny)+1, tmp);
    }
    return f[x][y] = tmp;
}

int main(int argc,char* argv[])
{
    ms ( f , 0);
    r=read(),c=read();
    for (int i=1; i<=r; i++) 	
    {
        for (int j=1; j<=c; j++) a[i][j]= read(), vis[i][j]= 0;
    }
    int ans = 0;
    for (int i= 1; i<= r; i++) 
    {
        for (int j= 1; j<= c; j++) 
        {
            f[i][j] = dfs( i, j);
            ans = max( f[i][j], ans);
        }
    }
    printf ("%d
", ans);
    return 0;
}