POJ 1088 滑雪 -- 动态规划

题目地址：http://poj.org/problem?id=1088

Description

 1  2  3  4 5

16 17 18 19 6

15 24 25 20 7

14 23 22 21 8

13 12 11 10 9

Input

Output

Sample Input

5 5
1 2 3 4 5
16 17 18 19 6
15 24 25 20 7
14 23 22 21 8
13 12 11 10 9

Sample Output

25

#include <stdio.h>

int matrix[100][100];
int dp[100][100];
int R;
int C;

int Max (int a, int b, int c, int d){
	int max1 = (a > b) ? a : b;
	int max2 = (c > d) ? c : d;
	return (max1 > max2) ? max1 : max2;
}

// dp[i][j] = max(dp[i-1][j], dp[i+1][j], dp[i][j-1], dp[i][j+1]) + 1
int MaxLength(int i, int j){
	if (dp[i][j] > 0)
		return dp[i][j];
	int a = 0;
	int b = 0;
	int c = 0;
	int d = 0;
	if (i-1 >= 0 && matrix[i][j] > matrix[i-1][j]){
		a = MaxLength (i-1, j);
	}
	if (i+1 < R && matrix[i][j] > matrix[i+1][j]){
		b = MaxLength (i+1, j);
	}
	if (j-1 >= 0 && matrix[i][j] > matrix[i][j-1]){
		c = MaxLength (i, j-1);
	}
	if (j+1 < C && matrix[i][j] > matrix[i][j+1]){
		d = MaxLength (i, j+1);
	}
	return dp[i][j] = Max (a, b, c, d) + 1;
}

int main(void){
	int i, j;
	int max;

	while (scanf ("%d%d", &R, &C) != EOF){
		for (i=0; i<R; ++i)
			for (j=0; j<C; ++j){
				scanf ("%d", &matrix[i][j]);
				dp[i][j] = 0;
			}
		for (i=0; i<R; ++i){
			for (j=0; j<C; ++j){
				MaxLength (i, j);
			}
		}
		max = 0;
		for (i=0; i<R; ++i){
			for (j=0; j<C; ++j){
				if (max < dp[i][j]){
					max = dp[i][j];
				}
			}
		}
		printf ("%d\n", max);
	}

	return 0;
}

POJ 1088 滑雪 -- 动态规划

原文：http://blog.csdn.net/jdplus/article/details/19690187