From 66cb34aa5536fc61aa4acaed66dcfae5d457629e Mon Sep 17 00:00:00 2001
From: unknown <mbhumikasharma@gmail.com>
Date: Tue, 21 Oct 2025 15:08:52 -0700
Subject: [PATCH] Done Arrays2

---
 DisappearedNum.java | 21 ++++++++++++++++++
 LifeGame.java       | 52 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 DisappearedNum.java
 create mode 100644 LifeGame.java

diff --git a/DisappearedNum.java b/DisappearedNum.java
new file mode 100644
index 00000000..c810557f
--- /dev/null
+++ b/DisappearedNum.java
@@ -0,0 +1,21 @@
+class Solution {
+    public List<Integer> findDisappearedNumbers(int[] nums) {
+        List<Integer> result = new ArrayList<>();
+        HashSet<Integer> set = new HashSet<>();
+        int n = nums.length;
+
+        for (int i = 0; i < n; i++) {
+            set.add(nums[i]); // add all the elements to has set
+        }
+
+        for (int i = 1; i <= n; i++) {
+            if (!set.contains(i)) { //check whether set contains the nu,ber or not
+                result.add(i);
+            }
+        }
+        return result;
+    }
+}
+
+Time complexity : O(n)
+space complexity: O(n)
\ No newline at end of file
diff --git a/LifeGame.java b/LifeGame.java
new file mode 100644
index 00000000..b529f568
--- /dev/null
+++ b/LifeGame.java
@@ -0,0 +1,52 @@
+class Solution {
+    int[][] dirs;
+    int m,n;
+
+    public void gameOfLife(int[][] board) {
+
+        this.dirs = new int[][]{{-1,-1}, {-1,0}, {-1, 1}, {0, -1}, {0, 1}, {1,-1}, {1,0}, {1,1}};
+
+        this.m = board.length;
+        this.n = board[0].length;
+
+        for(int i=0; i<m; i++){
+            for(int j=0; j<n; j++){
+                int count = getCount(board, i, j);  // number of alive cells around it
+                if(board[i][j] == 0 && count == 3){
+                    board[i][j] = 3; // dead -> alive;
+                }else if(board[i][j] == 1 && (count < 2 || count >3)){
+                    board[i][j] = 2; // alive -> dead;
+                }
+            }
+        }
+
+        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 getCount(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;
+    }
+}
+
+
+Time complexity : O(m*n)
+Space Complexity : O(1)
\ No newline at end of file