xinguohenan

http://acm.pku.edu.cn/JudgeOnline/problem?id=1088

虽然对搞ACM的人很简单，但是对我这种非专业人士而言也有点难度，而且是第一次写记忆化搜索的dp。

#include<stdio.h>
int dp(int row,int col);
int calculated[100][100],r,c,min_x,min_y;
int sum[100][100],board[100][100],result;
int dx[4] = {0,0,1,-1} , dy[4] = {1,-1,0,0};
int main()
{
    int i,j,k,min = 10001;
    scanf("%d%d",&r,&c);
    for (i = 0;i < 100;i++)
    for (j = 0;j < 100;j++)
    { sum[i][j] = 1;
        calculated[i][j] = 0;
    }
    for (i = 0;i < r;i++)
    for (j = 0;j < c;j++)
    {
        scanf("%d",&board[i][j]);
        if (board[i][j] < min)
        {
                        min = board[i][j];
                        min_x = i;
                        min_y = j;
        }
    }
    result = 0;
    for (i = 0;i < r;i++)
    for (j = 0;j < c;j++)
    {
        dp(i,j);
        if (result < sum[i][j])
           result = sum[i][j];
    }
    printf("%d\n",result);
    return 0;
}

int dp(int row,int col)
{
    int i,j,temp_row,temp_col,temp_sum;
    if (calculated[row][col])
       return sum[row][col];
    else
    {
        for (i = 0;i < 4;i++)
        {
            temp_row = row + dx[i];
            temp_col = col + dy[i];
            if(temp_row >= 0 && temp_row < r && temp_col >= 0 && temp_col < c && board[temp_row][temp_col] > board[row][col])
            {
                temp_sum = dp(temp_row,temp_col) + 1;
                if (temp_sum > sum[row][col])
                   sum[row][col] = temp_sum;
            }
        }
        calculated[row][col] = 1;
        return sum[row][col];
    }
}