滑雪
Time Limit: 1000MS | Memory Limit: 65536K | |
Total Submissions: 103085 | Accepted: 39236 |
Description
Michael喜欢滑雪百这并不奇怪, 因为滑雪的确很刺激。可是为了获得速度,滑的区域必须向下倾斜,而且当你滑到坡底,你不得不再次走上坡或者等待升降机来载你。Michael想知道载一个区域中最长底滑坡。区域由一个二维数组给出。数组的每个数字代表点的高度。下面是一个例子
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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 |
一个人可以从某个点滑向上下左右相邻四个点之一,当且仅当高度减小。在上面的例子中,一条可滑行的滑坡为24-17-16-1。当然25-24-23-…-3-2-1更长。事实上,这是最长的一条。
Input
输入的第一行表示区域的行数R和列数C(1 <= R,C <= 100)。下面是R行,每行有C个整数,代表高度h,0<=h<=10000。
Output
输出最长区域的长度。
Sample Input
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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
1 |
25 |
深搜暴力
为节约时间只从可能作为起点(高度大于等于四周的点)的点开始寻找
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#include <cstdio> #include <string> #define MAX(a,b) (a>b)?a:b; int area[102][102]; int areanum[102][102]; int search(int x, int y) { if ((area[x][y] > area[x+1][y]) && (areanum[x][y] >= areanum[x+1][y])) { areanum[x+1][y] = areanum[x][y] + 1; search(x+1, y); } if ((area[x][y] > area[x-1][y]) && (areanum[x][y] >= areanum[x-1][y])) { areanum[x-1][y] = areanum[x][y] + 1; search(x-1, y); } if ((area[x][y] > area[x][y+1]) && (areanum[x][y] >= areanum[x][y+1])) { areanum[x][y+1] = areanum[x][y] + 1; search(x, y+1); } if ((area[x][y] > area[x][y-1]) && (areanum[x][y] >= areanum[x][y-1])) { areanum[x][y-1] = areanum[x][y] + 1; search(x, y-1); } return 0; } int main() { int r,c; scanf("%d%d", &r,&c); for (int i = 0; i <= 101; i++) for (int j = 0; j <= 101; j++) { area[i][j] = 2147483647; areanum[i][j] = 1; } for (int i = 1; i <= r; i++) for (int j = 1; j <= c; j++) scanf("%d", &area[i][j]); for (int i = 1; i <= r; i++) for (int j = 1; j <= c; j++) if ((area[i][j]>=(area[i+1][j]==2147483647?0:area[i + 1][j])) && (area[i][j]>=(area[i - 1][j] == 2147483647 ? 0 : area[i - 1][j])) && (area[i][j]>=(area[i ][j-1] == 2147483647 ? 0 : area[i ][j-1])) && (area[i][j]>=(area[i ][j+1] == 2147483647 ? 0 : area[i][j+1])))search(i, j); int print=0; for (int i = 1; i <= r; i++) { for (int j = 1; j <= c; j++) { print = MAX(print, areanum[i][j]); ///printf("%d ", areanum[i][j]); } ///printf("\n"); } printf("%d", print); } |