【leetcode】二叉搜索树中的众数

int* answer;
int answerSize;
int base, count, maxCount;

void update(int x) {
    if (x == base) {
        ++count;
    } else {
        count = 1;
        base = x;
    }
    if (count == maxCount) {
        answer[answerSize++] = base;
    }
    if (count > maxCount) {
        maxCount = count;
        answerSize = 0;
        answer[answerSize++] = base;
    }
}

void dfs(struct TreeNode* o) {
    if (!o) {
        return;
    }
    dfs(o->left);
    update(o->val);
    dfs(o->right);
}

int* findMode(struct TreeNode* root, int* returnSize) {
    base = count = maxCount = 0;
    answer = malloc(sizeof(int) * 4001);
    answerSize = 0;
    dfs(root);
    *returnSize = answerSize;
    return answer;
}