算法问题实战策略 QUADTREE

#include <iostream>
#include <string>

using namespace std;

/*
4
w
xbwwb
xbwxwbbwb
xxwwwbxwxwbbbwwxxxwwbbbwwwwbb
=======================================
w
xwbbw
xxbwwbbbw
xxwbxwwxbbwwbwbxwbwwxwwwxbbwb
*/

int n;

string reverse(string::iterator& it)
{
    char head = *it;
    ++it;
    if (head == ‘b‘ || head == ‘w‘)
        return string(1, head);
    string upperLeft = reverse(it);
    string upperRight = reverse(it);
    string lowerLeft = reverse(it);
    string lowerRight = reverse(it);

    return string(1,‘x‘) + lowerLeft + lowerRight + upperLeft + upperRight;
}

int main()
{
    cin >> n;
    while (n--) {
        string s;
        cin >> s;
        string::iterator it = s.begin();
        cout << reverse(it) << endl;
    }

    return 0;
}