题解 | Problem D
#include <iostream>
using namespace std;
void dfs(string pre, string in) {
if (pre.empty()) return;
char root = pre[0];
int k = in.find(root);
dfs(pre.substr(1, k), in.substr(0, k));
dfs(pre.substr(k + 1), in.substr(k + 1));
cout << root;
}
int main() {
string pre, in;
while (cin >> pre >> in) {
dfs(pre, in);
cout << endl;
}
}
树生成的固定代码
