AddTwoNumbers.cpp

daiwb · daiwb · commit 15db99668c71 · 2013-01-22T17:57:56.000-08:00
diff --git a/LeetCode/AddTwoNumbers.cpp b/LeetCode/AddTwoNumbers.cpp
@@ -0,0 +1,40 @@
+#include <iostream>
+using namespace std;
+
+struct ListNode {
+    int val;
+    ListNode *next;
+    ListNode(int x) : val(x), next(NULL) {}
+};
+
+class Solution {
+public:
+    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
+        int add = 0;
+        ListNode *ret(NULL), *cur(NULL);
+        while (true) {
+            int s = add;
+            if (ret == NULL) {
+                s += l1->val + l2->val;
+            } else {
+                if (l1 != NULL) s += l1->val;
+                if (l2 != NULL) s += l2->val;
+            }
+            ListNode *t = new ListNode(s % 10);
+            add = s / 10;
+            
+            if (ret == NULL) ret = t;
+            else cur->next = t;
+            cur = t;
+            
+            if (l1 != NULL) l1 = l1->next;
+            if (l2 != NULL) l2 = l2->next;
+            if (l1 == NULL && l2 == NULL) break;
+        }
+        if (add == 1) {
+            ListNode *t = new ListNode(1);
+            cur->next = t;
+        }
+        return ret;
+    }
+};
