题解 | #二叉树遍历#

#include <iostream>
#include <vector>
using namespace std;
string a, b;
vector<char>res;
int na, nb;
void dfs(int la, int ra, int lb, int rb)
{
    if(la > ra || lb > rb) return;
    int mid;
    for (int i = lb; i <= rb; i++)
    {
        if(b[i] == a[la])
        {
            mid = i;
            break;
        }
    }
    dfs(la + 1, la + mid -lb, lb, mid - 1);
    dfs(la + mid -lb + 1, ra, mid + 1, rb);
    res.push_back(a[la]);
}
int main() {
    while(cin >> a >> b)
    {
        res.clear();
        na = a.length();
        nb = b.length();
        dfs(0, na - 1, 0, nb - 1);
        for (int i = 0; i < res.size(); i++)
            cout << res[i];
        cout << endl;
    }
}
// 64 位输出请用 printf("%lld")