blob: 45ecbd99d8f8e2b462f591f4fd216ea825acb0f2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
// 103. Binary Tree Zigzag Level Order Traversal
// given the 'root' of a binary tree, return the zigzag level order traversal of
// its nodes' values (ie. from left to right, then right to left for the next
// level)
#include <math.h>
#include <stddef.h>
#include <stdlib.h>
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
};
int depth(struct TreeNode *root) {
if (root == NULL)
return 0;
else
return 1 + fmax(depth(root->left), depth(root->right));
}
int **zigzagLevelOrder(struct TreeNode *root, int *returnSize,
int **returnColumnSizes) {
int dep = depth(root);
if (dep == 0) {
*returnSize = 0;
return NULL;
}
*returnColumnSizes = malloc(dep * sizeof(int));
int **ans = malloc(dep * sizeof(int *)), ans_idx = 0;
struct TreeNode **q0 = malloc(1000 * sizeof(struct TreeNode *));
struct TreeNode **q1 = malloc(1000 * sizeof(struct TreeNode *));
int idx0 = 0, idx1 = 0;
q0[idx0] = root;
idx0 = 1;
while (idx0 || idx1) {
if (idx0) {
ans[ans_idx] = malloc(idx0 * sizeof(int));
returnColumnSizes[0][ans_idx] = idx0;
for (int i = idx0 - 1; i >= 0; i--) {
ans[ans_idx][idx0 - 1 - i] = q0[i]->val;
if (q0[i]->left) {
q1[idx1] = q0[i]->left;
idx1++;
}
if (q0[i]->right) {
q1[idx1] = q0[i]->right;
idx1++;
}
}
ans_idx++;
idx0 = 0;
} else {
ans[ans_idx] = malloc(idx1 * sizeof(int));
returnColumnSizes[0][ans_idx] = idx1;
for (int i = idx1 - 1 - i; i >= 0; i--) {
ans[ans_idx][idx1 - 1 - i] = q1[i]->val;
if (q1[i]->right) {
q0[idx0] = q1[i]->left;
idx0++;
}
}
ans_idx++;
idx1 = 0;
}
}
*returnSize = dep;
return ans;
}
|