poj 1088 滑雪

#include <iostream>
using namespace std;
int r,c,height[101][101],skate[101][101];
int dp(int i,int j)
{
    int up,down,left,right,max=0;
    if(i>1&&height[i][j]>height[i-1][j])
    {
        if(skate[i-1][j]!=0)
            down=skate[i-1][j];
        else
            down=dp(i-1,j);
        if(max<down)max=down;
    }
    if(i<r&&height[i][j]>height[i+1][j])
    {
        if(skate[i+1][j]!=0)
            up=skate[i+1][j];
        else
            up=dp(i+1,j);
        if(max<up)max=up;
    }
    if(j>1&&height[i][j]>height[i][j-1])
    {
        if(skate[i][j-1]!=0)
            left=skate[i][j-1];
        else
            left=dp(i,j-1);
        if(max<left)max=left;
    }
    if(j<c&&height[i][j]>height[i][j+1])
    {
        if(skate[i][j+1]!=0)
            right=skate[i][j+1];
        else 
            right=dp(i,j+1);
        if(max<right)max=right;
    }
    skate[i][j]=1+max;
    return skate[i][j];
}
int main()
{
    int i,j,max=0;
    scanf("%d%d",&r,&c);
    for(i=1;i<=r;i++)
        for(j=1;j<=c;j++)
            scanf("%d",&height[i][j]);
    for(i=1;i<=r;i++)
        for(j=1;j<=c;j++)
            dp(i,j);
    for(i=1;i<=r;i++)
        for(j=1;j<=c;j++)
            if(skate[i][j]>max)
                max=skate[i][j];
    printf("%d\n",max);
    return 0;
}