后序中序求层序

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <string>
#include <stack>
#include <queue>
using namespace std;
const int NI = 50;
int n, post[NI], in[NI];
struct node {
    int num;
    struct node *left;
    struct node *right;
};
struct node *CreatNode(int n) {
    struct node *tmp = (struct node *)malloc(sizeof(struct node));
    tmp->num = n;
    tmp->left = tmp->right = NULL;
    return tmp;
}
struct node *BuildTree(int pl, int pr, int il, int ir) {
    if(pl > pr || il > ir) return NULL;
    struct node *root = CreatNode(post[pr]);
    int p;
    for(int i = il; i <= ir; i++) {
        if(in[i] == post[pr]) {
            p = i; break;
        }
    }
    root->left = BuildTree(pl, pl+p-il-1, il, p-1);
    root->right = BuildTree(pl+p-il, pr-1, p+1, ir);
    return root;
};
vector<int> v;
void bfs(struct node *root) {
    queue<struct node*> q;
    q.push(root);
    while(!q.empty()) {
        struct node *t = q.front();
        v.push_back(t->num);
        q.pop();
        if(t->left) q.push(t->left);
        if(t->right) q.push(t->right);
    }
}
int main() {
    scanf("%d", &n);
    for(int i = 0; i < n; i++) {
        scanf("%d", &post[i]);
    }
    for(int i = 0; i < n; i++) {
        scanf("%d", &in[i]);
    }
    struct node *root = BuildTree(0, n-1, 0, n-1);
    bfs(root);
    printf("%d", v[0]);
    for(int i = 1; i < n; i++) {
        printf(" %d", v[i]);
    }
    printf("\n");
    return 0;
}