icameling

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */

icameling

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:

icameling

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:

icameling

class Solution {
public:
    bool isAnagram(string s, string t) {
        if (s.size() != t.size()) return false;

        int table[26] = {0};
        for (int i = 0; i < s.size(); ++i) {
            table[s[i] - 'a']++;
            table[t[i] - 'a']--;
        }

icameling

class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        unordered_set<int> same_set;
        unordered_set<int> num1_set(nums1.begin(), nums1.end());
        for (auto num : nums2) {
            if (num1_set.find(num) != num1_set.end())
                same_set.insert(num);
        }

icameling

class Solution {
public:
    bool isHappy(int n) {
        unordered_set<int> nums;
        
        int sum = 0;
        while (sum != 1) {
            sum = 0;
            while (n > 0) {
                int k = n % 10;

icameling

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        unordered_map<int, int> nums_map;
        for (int i = 0; i < nums.size(); ++i){
            int k = target - nums[i];
            auto iter = nums_map.find(k);
            if (iter != nums_map.end()) {
                return {i, nums_map[k]}; 
            }

icameling

class Solution {
public:
    int fourSumCount(vector<int>& nums1, vector<int>& nums2, vector<int>& nums3, vector<int>& nums4) {
        int ret = 0;
        unordered_map<int, int> ab_map;
        for (int a : nums1) {
            for (int b : nums2) {
                ab_map[a+b]++;
            }
        }

icameling

class Solution {
public:
    bool canConstruct(string ransomNote, string magazine) {
	    if (ransomNote.size() > magazine.size()) return false;

        int table[26] = {0};
        for (int i = 0; i < magazine.size(); ++i) {
            table[magazine[i] - 'a']++;
        }
        for (int i = 0; i < ransomNote.size(); ++i) {

icameling

class Solution {
public:

    inline void forward(vector<int>& nums, int k, int& j) {
        while (j < k && nums[j] == nums[j+1]) {
            j++;
        }
    }

    inline void backward(vector<int>& nums, int j, int& k) {