[algospot][분할정복] 쿼드 트리 뒤집기 : https://www.algospot.com/judge/problem/read/QUADTREE

[REFACTORING]QUADTREE.cpp

#include<iostream>
#include<string>
#include<vector>

using namespace std;

/*
 * 시간복잡도 : O(N)
 * 공간복잡도 : O(N)
 */

string solve(string::iterator& it) {

	char head = *it;
	it++;

	if (head == 'w' || head == 'b') {
		return string(1, head); // char to string
	}
	
	vector<string> arr(4);
	for (int i = 0; i < 4; i++) {
		arr[i] = solve(it);
	}

	// if head not 'w' or 'b' -> must 'x'.
	return 'x' + arr[2] + arr[3] + arr[0] + arr[1];
}

int main() {
	int N;
	cin >> N;
	while (N--) {
		string input;
		cin >> input;
		string::iterator it = input.begin();
		cout << solve(it) << endl;
	}
	return 0;
}