FAANMG | Arrays-2

DisappearedNumbers.java

@@ -0,0 +1,15 @@
+class DisappearedNumbers {
+    public List<Integer> findDisappearedNumbers(int[] nums) {
+
+        List<Integer> output = new ArrayList<>();
+
+        for(int i = 0; i<nums.length;i++) {
+            int idx = Math.abs(nums[i]) - 1;
+            if(nums[idx] > 0) nums[idx] = -1 * nums[idx];
+        }
+        for(int i = 0; i<nums.length;i++) {
+            if(nums[i] > 0) output.add(i+1);
+        }
+        return output;
+    }
+}

GameOfLife.java

@@ -0,0 +1,47 @@
+class GameOfLife {
+
+    int[][] dirs;
+
+    public void gameOfLife(int[][] board) {
+        dirs = new int[][] {{-1,-1}, {-1, 0}, {-1,1}, {0, -1}, {0, 1}, {1, -1}, {1,0}, {1,1}};
+
+        for(int i = 0; i<board.length;i++) {
+            for(int j=0;j<board[0].length;j++) {
+                int aliveCount = getAliveCount(board, i, j);
+
+                if(board[i][j] == 0 || board[i][j] == 2) {
+                    if(aliveCount == 3) {
+                        board[i][j] = 2;  // 2 Dead - Alive
+                    }
+                } else {
+                    if(aliveCount < 2 || aliveCount > 3) {
+                        board[i][j] = 3; // 3 Alive - Dead
+                    }
+                }
+            }
+        }
+
+        for(int i = 0; i<board.length;i++) {
+            for(int j=0;j<board[0].length;j++) {
+                if(board[i][j] == 2) board[i][j] = 1;
+                else if(board[i][j] == 3) board[i][j] = 0;
+            }
+        }
+
+
+    }
+
+    public int getAliveCount(int[][] board, int i, int j) {
+        int count = 0;
+        for(int[] dir : dirs) {
+            int row = i + dir[0];
+            int col = j + dir[1];
+
+            if(row >=0 && col >=0 && row < board.length && col < board[0].length && (board[row][col] == 1 || board[row][col] == 3)) {
+                count++;
+            }
+        }
+
+        return count;
+    }
+}