|Tyvj|动态规划|P1004 滑雪

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};
const int maxrc = 100 + 5;
int r,c;
int map[maxrc][maxrc];
int f[maxrc][maxrc];
//设f[i][j]为到达[i,j]时最优值
//f[i][j] = max{f[i+a][i+b] | a和b是4个坐标增量，map[i][j]<map[i+a][i+b]}
int dfs (int x, int y)
{
if (f[x][y]!=0) return f[x][y];//算过
int maxt = 1;
int t;
for (int i=0;i<4;i++)
{
int tx = x + dx[i], ty = y + dy[i];
if (tx>0&&ty>0&&tx<=r&&ty<=c&&map[tx][ty]>map[x][y])
{
t = dfs(tx,ty)+1;
maxt = max(t, maxt);
}
}
f[x][y] = maxt;
return maxt;
}
int main ()
{
scanf("%d%d", &r, &c);
for (int i=1;i<=r;i++)
for (int j=1;j<=c;j++)
scanf("%d", &map[i][j]);
memset(f, 0, sizeof(f));
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(ans, f[i][j]);
}
printf("%d\n", ans);
return 0;
}