中序后序到先序 洛谷P1030

洛谷P1030

输入中序先序序列，输出后序

l1-l2为当前中序遍历序列
l3-l4为当前后序遍历序列

#include<bits/stdc++.h>
using namespace std;

string a, b;

struct node{
    char self;
    int left, right;
}t[200];

void build(int l1, int l2, int l3, int l4) {
    for (int i = l1; i <= l2; i++) {
        if (a[i] == b[l4]) {
            cout << a[i];
            build(l1, i-1, l3, l3+i-1-l1);
            build(i+1, l2, l3+i-l1, l4-1);
        }
    }
}

int main() {
    cin >> a >> b;
    build(0, a.length()-1, 0, a.length()-1);
}