标签:dfs
Red and Black
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 8909 Accepted Submission(s): 5533
Problem Description
There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can‘t move on red tiles, he can move only on black tiles.
Write a program to count the number of black tiles which he can reach by repeating the moves described above.
Input
The input consists of multiple data sets. A data set starts with a line containing two positive integers W and H; W and H are the numbers of tiles in the x- and y- directions, respectively. W and H are not more than 20.
There are H more lines in the data set, each of which includes W characters. Each character represents the color of a tile as follows.
‘.‘ - a black tile
‘#‘ - a red tile
‘@‘ - a man on a black tile(appears exactly once in a data set)
Output
For each data set, your program should output a line which contains the number of tiles he can reach from the initial tile (including itself).
Sample Input
6 9
....#.
.....#
......
......
......
......
......
#@...#
.#..#.
11 9
.#.........
.#.#######.
.#.#.....#.
.#.#.###.#.
.#.#..@#.#.
.#.#####.#.
.#.......#.
.#########.
...........
11 6
..#..#..#..
..#..#..#..
..#..#..###
..#..#..#@.
..#..#..#..
..#..#..#..
7 7
..#.#..
..#.#..
###.###
...@...
###.###
..#.#..
..#.#..
0 0
Sample Output
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;
char color[25][25];
int ans;
int w, h;
int x, y;
int dx[]= {1, -1, 0, 0};
int dy[]= {0, 0, 1, -1};
void dfs(int x, int y, int w, int h)
{
ans++;
color[x][y]='#';
for(int i=0; i<4; i++)
{
x=x+dx[i];
y=y+dy[i];
if(x>=0 && x<h && y>=0 && y<w && color[x][y]=='.')
dfs(x, y, w, h);
x-=dx[i]; //要特别注意还原数据
y-=dy[i];
}
}
int main()
{
while(scanf("%d%d", &w, &h)!=EOF)
{
if(w==0 && h==0)
break;
ans=0;
memset(color, 0, sizeof(color));
for(int i=0; i<h; i++)
{
scanf("%s", color[i]);
for(int j=0; j<w; j++)
{
if(color[i][j]=='@')
{
x=i;
y=j;
break;
}
}
}
dfs(x, y, w, h);
cout<<ans<<endl;
}
return 0;
}
HDU 1312:Red and Black,布布扣,bubuko.com
HDU 1312:Red and Black
标签:dfs
原文地址:http://blog.csdn.net/u013487051/article/details/37350929