POJ 2255-Tree Recovery

题意：

       树的前，中序遍历求后序遍历。基础题。

 

 

 

 

 

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code

#include <iostream>

#include <string>

using namespace std;

string sq, sh;

int len;

void make (int l, int r, int t, int w) {

	if (l > r || t > w) return;

	char s = sq[l];

	int i;

	for (i = 0; i < len; i++) if (sh[i] == s) break;

	int k = i - t;

	make (l + 1, l + k, t, i - 1);

	make (l + k + 1, r, i+1, w);

	cout << s;

}

int main() {

	while (cin >> sq >> sh) {

		len = (int) sq.size() - 1;

		make (0, len, 0, len);

		cout << endl;

	}

	return 0;

}