diff --git a/FindAllNumbersDisappearedInAnArray.java b/FindAllNumbersDisappearedInAnArray.java
new file mode 100644
index 00000000..55b0b5ca
--- /dev/null
+++ b/FindAllNumbersDisappearedInAnArray.java
@@ -0,0 +1,20 @@
+// Time Complexity :O(n)
+// Space Complexity :O(n)
+// Did this code successfully run on Leetcode :yes
+// Any problem you faced while coding this :no
+
+class Solution {
+    public List<Integer> findDisappearedNumbers(int[] nums) {
+        List<Integer> answer = new ArrayList<>();
+        HashSet<Integer> set = new HashSet<>();
+        for(int i=0;i<nums.length;i++){
+            set.add(nums[i]);
+        }
+        for(int i=1;i<=nums.length;i++){
+            if(!set.contains(i)) {
+                answer.add(i);
+            }
+        }
+        return answer;
+    }
+}
diff --git a/GameOfLife.java b/GameOfLife.java
new file mode 100644
index 00000000..4a71fabd
--- /dev/null
+++ b/GameOfLife.java
@@ -0,0 +1,47 @@
+// Time Complexity :O(m*n)
+// Space Complexity :O(1)
+// Did this code successfully run on Leetcode :yes
+// Any problem you faced while coding this :no
+
+class Solution {
+    int[][] dirs;
+    int m,n;
+
+    public void gameOfLife(int[][] board) {
+
+        dirs = new int[][]{{-1,-1}, {-1,0}, {-1, 1}, {0, -1}, {0, 1}, {1,-1}, {1,0}, {1,1}};
+        m = board.length;
+        n = board[0].length;
+        for(int i=0; i<m; i++){
+            for(int j=0; j<n; j++){
+                int count = count(board, i, j);
+                if(board[i][j] == 0 && count == 3){
+                    board[i][j] = 3; 
+                }else if(board[i][j] == 1 && (count < 2 || count >3)){
+                    board[i][j] = 2; 
+                }
+            }
+        }
+        for(int i=0; i<m; i++){
+            for(int j=0; j<n; j++){
+                if(board[i][j] == 2){
+                    board[i][j] = 0;
+                }else if(board[i][j] == 3){
+                    board[i][j] = 1;
+                }
+            }
+        }
+    }
+    private int count(int[][] board, int i, int j){
+        int count = 0;
+        for(int[] dir: dirs){
+            int r = i + dir[0];
+            int c = j + dir[1];
+            if(r>=0 && c>=0 && r<m && c<n){ 
+                if(board[r][c] == 1 || board[r][c] == 2) count++;
+            }
+        }
+        return count;
+    }
+}
+