UVA297 四分树 Quadtrees

知识点：多叉树的递归遍历

虽然是多叉树，其实递归遍历也是和二叉树一样的，道理是一样的，这里要注意，我们输入一个节点的数据，然后就要去递归这个节点下面的内容，这才算对整个节点的子树操作完成了，以前做过这个题，15分钟过了

#include 
 
using namespace std;
 
int a[35][35];
 
void solve(char ch, int x, int y, int level) {
	if (ch != 'p') {
		for (int i = x; i < x + (1 << level); i++) {
			for (int j = y; j < y + (1 << level); j++) {
				a[i][j] += (ch == 'f' ? 1 : 0);
			}
	    }
	} else {
		char t;
		cin >> t; solve(t, x, y, level - 1);
		cin >> t; solve(t, x + (1 << (level - 1)), y, level - 1);
		cin >> t; solve(t, x, y + (1 << (level - 1)), level - 1);
		cin >> t; solve(t, x + (1 << (level - 1)), y + (1 << (level - 1)), level - 1);
	}
}
 
int main() {
	int T;
	cin >> T;
	while (T--) {
		memset(a, 0, sizeof(a));
		char ch;
		cin >> ch;
		solve(ch, 0, 0, 5);
		cin >> ch;
		solve(ch, 0, 0, 5);
		int ans = 0;
		for (int i = 0; i < 32; i++) {
			for (int j = 0; j < 32; j++) {
				if (a[i][j]) ans++;
			}
		}
		cout << "There are " << ans << " black pixels.\n";
	}
	return 0;
}