diff --git a/src/main/java/com/dota/bit/_2317/Solution.java b/src/main/java/com/dota/bit/_2317/Solution.java
new file mode 100644
index 0000000..25a75e4
--- /dev/null
+++ b/src/main/java/com/dota/bit/_2317/Solution.java
@@ -0,0 +1,11 @@
+package com.dota.bit._2317;
+
+class Solution {
+    public int maximumXOR(int[] nums) {
+        var x = 0;
+        for (int num : nums) {
+            x |= num;
+        }
+        return x;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/dota/bit/_2527/Solution.java b/src/main/java/com/dota/bit/_2527/Solution.java
new file mode 100644
index 0000000..2c31d8d
--- /dev/null
+++ b/src/main/java/com/dota/bit/_2527/Solution.java
@@ -0,0 +1,11 @@
+package com.dota.bit._2527;
+
+class Solution {
+    public int xorBeauty(int[] nums) {
+        int x = 0;
+        for (int num : nums) {
+            x ^= num;
+        }
+        return x;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/dota/bit/_2564/Solution.java b/src/main/java/com/dota/bit/_2564/Solution.java
new file mode 100644
index 0000000..80206b7
--- /dev/null
+++ b/src/main/java/com/dota/bit/_2564/Solution.java
@@ -0,0 +1,31 @@
+package com.dota.bit._2564;
+
+import java.util.HashMap;
+
+class Solution {
+	public int[][] substringXorQueries(String s, int[][] queries) {
+		var map = new HashMap<String, Integer>();
+		for (int i = 0; i < s.length(); i++) {
+			for (int j = 0; j < 30 && i+j<s.length(); j++) {
+				var t = s.substring(i, i+j+1);
+				if (!map.containsKey(t)) {
+					map.put(t, i);
+				}
+			}
+		}
+
+		var res = new int[queries.length][2];
+		var idx = 0;
+		for (int[] query : queries) {
+			int x = query[0] ^ query[1];
+			var b = Integer.toBinaryString(x);
+			int i = map.getOrDefault(b, -1);
+			if (i==-1) {
+				res[idx++] = new int[]{-1,-1};
+			} else {
+				res[idx++] = new int[]{i, i + b.length() - 1};
+			}
+		}
+		return res;
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/com/dota/bit/_2683/Solution.java b/src/main/java/com/dota/bit/_2683/Solution.java
index a6326e5..23edcce 100644
--- a/src/main/java/com/dota/bit/_2683/Solution.java
+++ b/src/main/java/com/dota/bit/_2683/Solution.java
@@ -2,6 +2,12 @@ package com.dota.bit._2683;
 
 class Solution {
     public boolean doesValidArrayExist(int[] derived) {
-        return false;
+        int n = derived.length;
+        int[] res = new int[n];
+        res[0] = 1;
+        for (int i = 1; i < derived.length; i++) {
+            res[i] = derived[i - 1] ^ res[i-1];
+        }
+        return (res[0]^res[n-1]) == derived[n-1];
     }
 }
\ No newline at end of file