题解 | #二叉树遍历#

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define len 2000

typedef struct node{
    char val;
    struct node*lchild;
    struct node*rchild;
}node;

node*initial_node(char c){
    node*nd = (node*)malloc(sizeof(node));
    nd->val = c;
    nd->lchild = NULL;
    nd->rchild = NULL;
    return nd;
}

int i;
node*build_tree(char str[]){
    i++;
    if(str[i]!='#'&&i<strlen(str)){
        node*nd = initial_node(str[i]);
        nd->lchild = build_tree(str);
        nd->rchild = build_tree(str);
        return nd;
    }
    return NULL;
}

void LNR(node*tree){
    if(tree!=NULL){
        LNR(tree->lchild);
        printf("%c ",tree->val);
        LNR(tree->rchild);
    }
}

int main(){
    char str[len];
    while(scanf("%s",str)!=EOF){
        i = -1;
        node*tree = build_tree(str);
        LNR(tree);
        printf("\n");
    }
}