题解 | #二叉树遍历#

#include <iostream>
#include <string>
#include<cstring>
#include <cstdio>
using namespace std;
typedef struct Binode {
    char data;
    struct Binode* lnode;
    struct Binode* rnode;
    Binode(char c): data(c), lnode(NULL), rnode(NULL) {}
};
Binode* build(int& pos, string str) {
    char c = str[pos++];
    if (c == '#') return NULL;
    Binode* b = new Binode(c);
    b->lnode = build(pos, str);
    b->rnode = build(pos, str);
    return b;
}

void midVisit(Binode* b) {
    if (b->lnode != NULL) {
        midVisit(b->lnode);
    }
    cout << b->data << " ";
    if (b->rnode != NULL) {
        midVisit(b->rnode);
    }

}
int main() {
    string str;
    while (cin >> str) { // 注意 while 处理多个 case
        int pos = 0;
        Binode* b = build(pos, str);
        midVisit(b);
    }
}
// 64 位输出请用 printf("%lld")