diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..da47135
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "Q3"]
+	path = Q3
+	url = https://github.com/qyyao/Q3
diff --git a/Q1.java b/Q1.java
new file mode 100644
index 0000000..b9bb780
--- /dev/null
+++ b/Q1.java
@@ -0,0 +1,51 @@
+import java.util.Arrays;
+
+public class Q1 {
+
+    public static void findPairs(int[] testArray, int targetSum) {
+    	
+        //sort the array
+        Arrays.sort(testArray);
+
+        //initialize an index to keep track of placement
+        int i = 0;
+        int j;
+
+        //find the length of the array
+        int length = testArray.length;
+
+        //we only have to check numbers up to half of the target sum
+        while (testArray[i] <= targetSum / 2) {
+            //make sure we do not calculate duplicates by not testing cases where testArray[i] is identical to the one previous
+
+            if (i > 0 ? testArray[i] != testArray[i - 1] : testArray[i] <= targetSum / 2) {
+
+                for (j = i + 1; j < length; j++) {
+
+                    if (testArray[j] == targetSum - testArray[i]) {
+                        System.out.println("(" + testArray[i] + "," + testArray[j] + ")");
+                        i++;
+                        break;
+                    }
+
+                    if (j==length-1){	//when you reach the end of the array without finding a pair, accumulate i
+                    	i++;
+                    }
+                }
+            }
+
+            else{
+            	i++;
+            }
+        }
+    }
+
+
+    public static void main(String[] args) {
+        int[] testArray = {2, 4, 3, 3, 3, 5, 5, 5, 5, 2, 6, 8, };
+        int targetSum = 10;
+
+        findPairs(testArray, targetSum);
+    }
+
+}
\ No newline at end of file
diff --git a/Q2.java b/Q2.java
new file mode 100644
index 0000000..875a3ef
--- /dev/null
+++ b/Q2.java
@@ -0,0 +1,33 @@
+public class Q2{
+
+	public static boolean isPalindrome(String testString) {
+
+
+		//find the length of the string
+		int length = testString.length();
+
+		//compare each letter to the same letter in the reverse position
+		for (int i = 0; i < length/2; i++){
+			//subtract one more from the length as length is always one more than the last index
+			if (testString.charAt(i) != testString.charAt(length-i-1)){
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	public static void main(String[] args) {
+
+		boolean string1 = isPalindrome("remembertobuyeggs");
+		boolean string2 = isPalindrome("radar");
+		boolean string3 = isPalindrome("asdffdsa");
+		boolean string4 = isPalindrome("thisisnotapalindrome");
+
+
+		System.out.println(string1);
+		System.out.println(string2);
+		System.out.println(string3);
+		System.out.println(string4);
+	}
+}
\ No newline at end of file
diff --git a/Q3 b/Q3
new file mode 160000
index 0000000..03c1131
--- /dev/null
+++ b/Q3
@@ -0,0 +1 @@
+Subproject commit 03c1131caa4c9bbf0b67913fe45cc86aaff5294a