165. 구조체 트리 후위 순회의 k번째 노드

1#include <stdio.h>
2 
3struct Node {
4    int val;
5    struct Node *left;
6    struct Node *right;
7};
8 
9int cnt = 0;
10int found = -1;
11 
12void post(struct Node *n, int k) {
13    if (n == NULL) return;
14    post(n->left, k);
15    post(n->right, k);
16    cnt++;
17    if (cnt == k) found = n->val;
18}
19 
20int main() {
21    struct Node d = {4, NULL, NULL};
22    struct Node e = {9, NULL, NULL};
23    struct Node b = {2, &d, NULL};
24    struct Node c = {7, NULL, &e};
25    struct Node a = {5, &b, &c};
26    post(&a, 3);
27    printf("%d %d\n", found, cnt);
28    return 0;
29}