HDOJ题目2952Counting Sheep （DFS）

Counting Sheep

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2163    Accepted Submission(s): 1426

Problem Description

A while ago I had trouble sleeping. I used to lie awake, staring at the ceiling, for hours and hours. Then one day my grandmother suggested I tried counting sheep after I'd gone to bed. As always when my grandmother suggests things, I decided to try it out. The only problem was, there were no sheep around to be counted when I went to bed.


Creative as I am, that wasn't going to stop me. I sat down and wrote a computer program that made a grid of characters, where # represents a sheep, while . is grass (or whatever you like, just not sheep). To make the counting a little more interesting, I also decided I wanted to count flocks of sheep instead of single sheep. Two sheep are in the same flock if they share a common side (up, down, right or left). Also, if sheep A is in the same flock as sheep B, and sheep B is in the same flock as sheep C, then sheeps A and C are in the same flock.


Now, I've got a new problem. Though counting these sheep actually helps me fall asleep, I find that it is extremely boring. To solve this, I've decided I need another computer program that does the counting for me. Then I'll be able to just start both these programs before I go to bed, and I'll sleep tight until the morning without any disturbances. I need you to write this program for me.

 

Input

The first line of input contains a single number T, the number of test cases to follow.

Each test case begins with a line containing two numbers, H and W, the height and width of the sheep grid. Then follows H lines, each containing W characters (either # or .), describing that part of the grid.

 

Output

For each test case, output a line containing a single number, the amount of sheep flock son that grid according to the rules stated in the problem description.

Notes and Constraints
0 < T <= 100
0 < H,W <= 100

 

Sample Input

24 4#.#..#.##.##.#.#3 5###.#..#..#.###

 

Sample Output

63

 

Source

IDI Open 2009

 

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 ac代码

#include<stdio.h>#include<string.h>int dx[4]={1,0,-1,0};int dy[4]={0,1,0,-1};char map[110][110],v[110][110];int cot,n,m;void dfs(int x,int y){int i;if(x<0||x>=n)return;if(y<0||y>=m)return;if(v[x][y]||map[x][y]=='.')return;v[x][y]=1;for(i=0;i<4;i++){dfs(x+dx[i],y+dy[i]);}}int main(){//int n,m;int t;scanf("%d",&t);while(t--){int i,j;scanf("%d%d",&n,&m);for(i=0;i<n;i++)scanf("%s",&map[i]);cot=0;memset(v,0,sizeof(v));for(i=0;i<n;i++){for(j=0;j<m;j++)if(!v[i][j]&&map[i][j]=='#'){cot++;dfs(i,j);}}printf("%d\n",cot);}}