Solution "Longest Substring Without Repeating Characters" on Leet Code

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        string candidate_str = "";
        string checking_str = "";
        size_t position = std::string::npos;
        for (auto& ch : s)
        {
            position = checking_str.find(ch);
            if (position …

Solution "Add Two Numbers" on Leet Code

/**
 * 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 …

Two Sum solution on Leet Code

The simple solution

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        for (int i = 0; i < nums.size(); ++i)
        {
            for (int j = i + 1; j < nums.size(); ++j) …