poj 1088 滑雪 记忆化搜索

 1 #include <cstdio>
 2 #include <cmath>
 3 #include <cstring>
 4 #include <ctime>
 5 #include <iostream>
 6 #include <algorithm>
 7 #include <set>
 8 #include <vector>
 9 #include <sstream>
10 #include <queue>
11 #include <typeinfo>
12 #include <fstream>
13 #include <map>
14 #include <stack>
15 typedef long long ll;
16 using namespace std;
17 #define test freopen("1.txt","r",stdin)
18 #define maxn 2000001
19 #define mod 10007
20 #define eps 1e-9
21 const int inf=0x3f3f3f3f;
22 const ll infll = 0x3f3f3f3f3f3f3f3fLL;
23 inline int read()
24 {
25     ll x=0,f=1;char ch=getchar();
26     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
27     while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
28     return x*f;
29 }
30 inline void out(int x) {
31    if(x>9) out(x/10);
32    putchar(x%10+‘0‘);
33 }
34 //**************************************************************************************
35 int n,m;
36 int a[105][105];
37 int dp[105][105];
38 int dy[4]={-1,1,0,0};
39 int dx[4]={0,0,-1,1};
40 int cal[105][105];
41 void init()
42 {
43     n=read();m=read();
44     for(int i=1;i<=n;i++)
45         for(int j=1;j<=m;j++)
46             {a[i][j]=read();dp[i][j]=1;}
47 }
48 bool check(int y,int x)
49 {
50     if(y<1||y>n||x<1||x>m)
51         return 0;
52     return 1;
53 }
54 int dfs(int y,int x)
55 {
56     if(cal[y][x]) return dp[y][x];
57     int maxl=dp[y][x];
58     for(int i=0;i<4;i++)
59     {
60         int newx=x+dx[i];int newy=y+dy[i];
61         if(check(newy,newx)&&a[newy][newx]<a[y][x])
62         {
63             maxl=max(maxl,dfs(newy,newx)+1);
64         }
65     }
66     cal[y][x]=1;
67     return dp[y][x]=maxl;
68 }
69 int main()
70 {
71     init();
72     int ans=-1;
73     for(int y=1;y<=n;y++)
74         for(int x=1;x<=m;x++)
75     {
76         ans=max(ans,dfs(y,x));
77     }
78     printf("%d\n",ans);
79     return 0;
80 }