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// 501. Find Mode in Binary Search Tree
#include "leetcode.h"
/*
* given the 'root' of a binary search tree with duplicates, return all the
* 'modes(s)' (ie. the most frequently occured element in it). if the tree has
* more than one mode, return them in any order.
*/
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
};
void order(struct TreeNode *root, int *cnt, int a[2][10000], int *max) {
if (!root)
return;
order(root->left, cnt, a, max);
if (!a[1][*cnt]) {
a[0][*cnt] = root->val;
a[1][*cnt]++;
} else if (root->val != a[0][*cnt]) {
(*cnt)++;
a[0][*cnt] = root->val;
a[1][*cnt]++;
} else {
a[1][*cnt]++;
}
if (*max < a[1][*cnt])
*max = a[1][*cnt];
order(root->right, cnt, a, max);
}
int *findMode(struct TreeNode *root, int *return_size) {
if (!root)
return NULL;
int a[2][10000] = {0};
int *max = (int *)malloc(sizeof(int));
int *cnt = (int *)malloc(sizeof(int));
*max = 0, *cnt = 0;
order(root, cnt, a, max);
int *ans = (int *)malloc(sizeof(int) * 10000);
*return_size = 0;
for (int i = 0; i <= *cnt; i++)
if (a[1][i] == *max)
ans[(*return_size)++] = a[0][i];
return ans;
}
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