diff --git a/Subarray sum equals k.java b/Subarray sum equals k.java
new file mode 100644
index 00000000..e69de29b
diff --git a/contiguous array.java b/contiguous array.java
new file mode 100644
index 00000000..aa07d09d
--- /dev/null
+++ b/contiguous array.java	
@@ -0,0 +1,24 @@
+// TimeComplexity: O(n)
+// SpaceComplexity: O(n)
+// Did this code successfully run on Leetcode : yes
+// Any problem you faced while coding this : no
+
+class Solution {
+    public int findMaxLength(int[] nums) {
+        int max = 0;
+        int sum = 0;
+        HashMap<Integer, Integer> map = new HashMap<>();
+        map.put(0,-1);
+        for(int i=0; i<nums.length; i++) {
+            sum = nums[i] == 0 ? sum-1 :sum+1;
+            if(map.containsKey(sum)) {
+                int curr = i - map.get(sum);
+                max = Math.max(max,curr);
+
+            } else {
+                map.put(sum,i);
+            }
+        }
+        return max;
+    }
+}
\ No newline at end of file
diff --git a/longest palindrome.java b/longest palindrome.java
new file mode 100644
index 00000000..e69de29b