A simple deep-search question, suitable for practice
1 // question link: http://poj.org/problem? Id = 2386
2 // solution: Define a lake as 1, define a land as 0, and search for each point by DFS.
3 # include <stdio. h>
4 # include <string. h>
5
6 int map [110] [110], vis [110] [110]; // map the simulated map. vis is used to mark whether the map has been accessed.
7 int dir [8] [2] = {-1, 0}, {-1, 1}, {0, 1}, {1, 1}, {1, 0 },{ 1,-1 },{ 0,-1 },{-1,-1 }}; // eight directions
8 int n, m;
9
10 void DFS (int x, int y ){
11 int I, J;
12 if (Map [x] [Y] = 0 | Vis [x] [Y] = 1) return; // accessed or the current location is blank
13 vis [x] [Y] = 1; // The tag point (x, y) has been accessed.
14 For (I = 0; I <8; I ++ ){
15 DFS (x + dir [I] [0], Y + dir [I] [1]); // recursively accesses eight directions
16}
17}
18
19 int main (){
20 int I, J;
21 char STR [110];
22 int ans;
23 while (scanf ("% d", & N, & M )! = EOF ){
24 memset (MAP, 0, sizeof (MAP); // all grids are initialized to land, including a circle around
25 memset (VIS, 0, sizeof (VIS); // all vertices are initialized to the inaccessible state.
26 For (I = 1; I <= N; I ++ ){
27 scanf ("% s", STR );
28 For (j = 1; j <= m; j ++ ){
29 If (STR [J-1] = 'W') {// 'W' is 1, '.' is 0
30 map [I] [J] = 1;
31}
32 else {
33 map [I] [J] = 0;
34}
35}
36}
37 ans = 0;
38 for (I = 1; I <= N; I ++ ){
39 For (j = 1; j <= m; j ++ ){
40 if (Map [I] [J] = 1 & Vis [I] [J] = 0) {// search all unaccessed points in DFS
41 ans ++;
42 DFS (I, j );
43}
44}
45}
46 printf ("% d \ n", ANS );
47}
48 return 0;
49}
POJ-2386-Lake counting
