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;
}