diff --git a/cpp/_2.cpp b/cpp/_2.cpp
new file mode 100644
index 0000000000..461a6c89ef
--- /dev/null
+++ b/cpp/_2.cpp
@@ -0,0 +1,64 @@
+/**
+ * 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) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
+        int carry =0;
+        ListNode* head = NULL;
+        ListNode* last = NULL;
+        while(l1&&l2){
+            int temp = l1->val+l2->val+carry;
+            ListNode* cur = new ListNode(temp%10);
+            carry = temp/10;
+            if(head == NULL){
+                head = cur;
+                last = cur;
+            }else{
+                last->next = cur;
+                last = cur;
+            }
+            l1=l1->next;
+            l2=l2->next;
+        }
+        while(l1){
+            int temp = l1->val+carry;
+            ListNode* cur = new ListNode(temp%10);
+            carry = temp/10;
+            if(head == NULL){
+                head = cur;
+                last = cur;
+            }else{
+                last->next = cur;
+                last = cur;
+            }
+            l1=l1->next;
+        }
+        while(l2){
+            int temp = l2->val+carry;
+            ListNode* cur = new ListNode(temp%10);
+            carry = temp/10;
+            if(head == NULL){
+                head = cur;
+                last = cur;
+            }else{
+                last->next = cur;
+                last = cur;
+            }
+            l2=l2->next;
+        }
+        if(carry){
+            ListNode* cur = new ListNode(carry);
+            last->next = cur;
+            cur->next= NULL;
+        }
+        return head;
+    }
+};
\ No newline at end of file
diff --git a/cpp/_5.cpp b/cpp/_5.cpp
new file mode 100644
index 0000000000..a4505084c3
--- /dev/null
+++ b/cpp/_5.cpp
@@ -0,0 +1,31 @@
+class Solution {
+public:
+        vector<vector<int> >dp;
+    int ispalin(int i,int j,string &s){
+        if(i>j||i==j)return 1;
+        if(dp[i][j]!=-1)return dp[i][j];
+
+        if(s[i]==s[j]){
+            return dp[i][j]=ispalin(i+1,j-1,s);
+        }
+        return dp[i][j]=0;
+    }
+    string longestPalindrome(string s) {
+        int n = s.length();
+        int jf=0;int af=0;
+        dp.resize(n,vector<int>(n,-1));
+        for(int i =0;i<n;i++){
+            for(int j=i;j<n;j++){
+                if(ispalin(i,j,s)&&jf-af<j-i){
+                    af=i;
+                    jf=j;
+                }
+            }
+        }
+        string sf="";
+        for(int i = af;i<=jf;i++){
+            sf+=s[i];
+        }
+        return sf;
+    }
+};
\ No newline at end of file