more some leetcode problems

leetcode_problemset/problemsets/add_two_numbers.cpp

@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct ListNode
+{
+    int val;
+    ListNode *next;
+    ListNode(int x) : val(x), next(NULL) {}
+};
+
+ListNode *addTwoNumbers(ListNode *l1, ListNode *l2)
+{
+
+    ListNode *l3 = new ListNode(0);
+    ListNode *current = l3;
+    int carry = 0;
+
+    while (l1 != NULL || l2 != NULL || carry != 0)
+    {
+        int sum = carry;
+        if (l1 != NULL)
+        {
+            sum += l1->val;
+            l1 = l1->next;
+        }
+        if (l2 != NULL)
+        {
+            sum += l2->val;
+            l2 = l2->next;
+        }
+        carry = sum / 10;
+        current->next = new ListNode(sum % 10);
+        current = current->next;
+    }
+
+    return l3->next;
+}

leetcode_problemset/problemsets/longest_substring_without_repeating.cpp

@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+pair<int,int> check_substring(string comp, int k) {
+
+    int size = comp.length();
+    unordered_map<char,int> rep;
+    for(int i = k; i < size; ++i) {
+        rep[comp[i]]++;
+        if(rep[comp[i]] >= 2)
+            return {k,i};
+    }
+
+    return {k,size};
+
+}
+
+int lengthOfLongestSubstring(string s) {
+
+    int ini = 0, size = s.length(), fin = 0;
+    for(int i = 0; i < size; ++i) {
+        pair<int,int> new_fin = check_substring(s,i);
+        if((new_fin.second - new_fin.first) > (fin-ini)) {
+            fin = new_fin.second;
+            ini = new_fin.first;
+        }
+        //cout << ini << " " << fin << endl;
+    }
+
+    return fin-ini;
+}
+
+
+// int main(){
+
+//     string s = "abcabcbb";
+//     int maxSub = lengthOfLongestSubstring(s);
+//     cout << maxSub << endl;
+
+//     return 0;
+// }