POJ 1088 滑雪（记忆化dfs）

#include<iostream>
#include<cstdio>
#include<set>
#include<string>
#include<string.h>
#include<cstring>
#include<vector>
#include<map>
#include<queue>
#include<stack>
#include<cctype>
#include<algorithm>
#include<sstream>
#include<utility>
#include<cmath>
#include<functional>
#define mt(a) memset(a,0,sizeof (a))
#define fl(a,b,c) fill(a,b,c)
#define SWAP(a,b,t) (t=a,a=b,b=t)

#define inf 1000000000+7
#define sp system("pause")

using namespace std;
typedef long long ll;

int G[120][120];
int H[120][120];
int disx[4] = { 0, 0, 1, -1 };
int disy[4] = { 1, -1, 0, 0 };
int n, m;
int  dfs(int x, int y)
{
if (H[x][y] != 0)return H[x][y];
int maxx = 0, s = 0;
for (int i = 0; i < 4; i++)
{
if (x + disx[i] >= 0 && x + disx[i] < n&&y + disy[i] >= 0 && y + disy[i] < m)
{
if (G[x][y]>G[x + disx[i]][y + disy[i]])
{
s = dfs(x + disx[i], y + disy[i]);
if (s>maxx)maxx = s;
}
}

}
H[x][y] = maxx+1;
return H[x][y];
}

int main()
{

cin >> n >> m;
mt(G);
mt(H);
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
scanf("%d", &G[i][j]);
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
H[i][j] = dfs(i, j);
}
}
int maxx = 0;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
maxx = max(maxx, H[i][j]);
}
printf("%d\n", maxx);
sp;
return 0;
}