50068. Tree Traversal
難度：4.4/5
注意紀錄的東西是從root到你的current就好，不用把每一步都記下來。1
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71#include <stdio.h>
#include "tree.h"
void print_node(Node* n){
printf("%d\n", n->label);
}
void traversal(Node *root, int N, int command[]){
Node* history[1024];
int idx = 0;
history[idx] = root;
for(int i = 0; i < N; i++){
int t = command[i];
if(t == 0){
print_node(history[idx]);
break;
}
else if(t == 1){
print_node(history[idx]);
}
else if(t == 2){
if(idx == 0){
print_node(history[idx]);
break;
}
else{
idx -= 1;
}
}
else if(t == 3){
if(history[idx]->left == NULL){
print_node(history[idx]);
break;
}
else{
history[idx + 1] = history[idx]->left;
idx += 1;
}
}
else if(t == 4){
if(history[idx]->right == NULL){
print_node(history[idx]);
break;
}
else{
history[idx + 1] = history[idx]->right;
idx += 1;
}
}
else if(t == 5){
if(idx == 0){
print_node(history[idx]);
break;
}
else if(history[idx - 1]->left == NULL || history[idx - 1]->right == NULL){
print_node(history[idx]);
break;
}
else{
if(history[idx] == history[idx - 1]->left){
history[idx] = history[idx - 1]->right;
}
else{
history[idx] = history[idx - 1]->left;
}
}
}
}
}