add linked-list-cycle, sum-of-two-integers

Author: sangyyypark

linked-list-cycle/sangyyypark.java

@@ -0,0 +1,28 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode(int x) {
+ *         val = x;
+ *         next = null;
+ *     }
+ * }
+ */
+public class Solution {
+    public boolean hasCycle(ListNode head) {
+        Set<ListNode> set = new HashSet();
+        ListNode current = head;
+        set.add(current);
+        while(current != null) {
+            if(set.contains(current.next)) {
+                return true;
+            }
+            current = current.next;
+            set.add(current);
+        }
+        return false;
+
+    }
+}
+

sum-of-two-integers/sangyyypark.java

@@ -0,0 +1,12 @@
+class Solution {
+    public int getSum(int a, int b) {
+        while(b != 0) {
+            int sum = a ^ b;
+            int carry = (a & b) << 1;
+            a = sum;
+            b = carry;
+        }
+        return a;
+    }
+}
+