DataWhale task 13

数组中的第K个最大元素

class Solution {
public:
    int findKthLargest(vector& nums, int k) {
        if(nums.empty()){
            return 0;
        }
        sort(nums.begin(), nums.end());
        int n = (nums.size()-k);
        return nums[n];
    }
};

存在重复元素

class Solution {
public:
    bool containsDuplicate(vector& nums) {

        bool flag =  false;
        unordered_map dict;
        for(int i =0;i

二叉搜索树中第K小的元素

class Solution {
private:
    vector nums;
public:
    void dfs(TreeNode* root){
        if(root==NULL){return ;}
        dfs(root->left);
        nums.push_back(root->val);
        dfs(root->right);
    }
    int kthSmallest(TreeNode* root, int k) {
        dfs(root);
        for(int i=0;i