poj1088 滑雪 dp+dfs记忆化

简单的搜索，不必多说了，初始状态下每个点能到达的长度是1，它本身。还有，注意关掉文件重定向，被坑好多次了。

代码如下：

 #include<cstdio>
 #include<algorithm>
 using namespace std;
 typedef unsigned int ui;
 typedef long long ll;
 typedef unsigned long long ull;
 #define pf printf
 #define mem(a,b) memset(a,b,sizeof(a))
 #define prime1 1e9+7
 #define prime2 1e9+9
 #define pi 3.14159265
 #define scand(x) scanf("%llf",&x)
 #define f(i,a,b) for(int i=a;i<=b;i++)
 #define scan(a) scanf("%d",&a)
 #define dbg(args) cout<<#args<<":"<<args<<endl;
 #define pb(i) push_back(i)
 #define ppb(x) pop_back(x)
 #define inf 0x3f3f3f3f
 #define maxn 105
 int n,m,t,a[maxn][maxn];
 int dp[maxn][maxn];//dp[i][j]:从(i,j)位置开始的最长道路的长度
 int dir[][]={,,,-,,,-,};
 bool vis[maxn][maxn];
 int dfs(int x,int y)
 {
     if(vis[x][y])return dp[x][y];
     vis[x][y]=true;
     int xx,yy;
     f(i,,)
     {
         xx=x+dir[i][];
         yy=y+dir[i][];
         if(xx<||xx>n||yy<||yy>m)continue;
         if(a[xx][yy]>=a[x][y])continue;
         dp[x][y]=max(dfs(xx,yy)+,dp[x][y]);
     }
     return dp[x][y];
 }
 int main()
 {
     //freopen("input.txt","r",stdin);
     //freopen("output.txt","w",stdout);
     //std::ios::sync_with_stdio(false);
     scan(n);
     scan(m);
     int ans=;
     f(i,,n)
         f(j,,m)
         {
             scan(a[i][j]);
             dp[i][j]=;
          }
         f(i,,n)
             f(j,,m)
             {
                 dfs(i,j);
                 ans=max(ans,dp[i][j]);
             }
                 pf("%d\n",ans);
  }