Array-2 solution

FindDisappearedNumbers.java

@@ -0,0 +1,29 @@
+//Time Complexity : O(n)
+//Space Complexity : O(1)
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class FindDisappearedNumbers {
+    List<Integer> result;
+    public List<Integer> findDisappearedNumbers(int[] nums) {
+        int n = nums.length;
+        result = new ArrayList<>();
+
+        for(int i = 0; i < n; i++) {
+            int index = Math.abs(nums[i]) - 1;
+            if(nums[index] > 0) {
+                nums[index] *= -1;
+            }
+        }
+
+        for(int i = 0; i < n; i++) {
+            if (nums[i] < 0) {
+                nums[i] *= -1;
+            } else {
+                result.add(i + 1);
+            }
+        }
+        return result;
+    }
+}

GameOfLife.java

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+//Time Complexity : O(m*n)
+//Space Complexity : O(1)
+
+public class GameOfLife {
+    public void gameOfLife(int[][] board) {
+        int m = board.length;
+        int n = board[0].length;
+        int[][] dirs = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}, {-1, -1}, {-1, 1}, {1, -1}, {1, 1}};
+        for(int r = 0; r < m; r++) {
+            for (int c = 0; c < n; c++) {
+                int live = 0;
+
+                for(int[] dir: dirs) {
+                    int nrow = r + dir[0];
+                    int ncol = c + dir[1];
+                    if(nrow >= 0 && ncol >=0 && nrow < m && ncol < n && (board[nrow][ncol] == 2 || board[nrow][ncol] == 1)) {
+                        live++;
+                    }
+                }
+
+                // 2 : live -> dead
+                // 3 : dead -> live
+                if(board[r][c] == 1 && (live < 2 || live > 3)) {
+                    board[r][c] = 2;
+                } else if (board[r][c] == 0 && live == 3) {
+                    board[r][c] = 3;
+                }
+
+            }
+        }
+        for(int r = 0; r < m; r++) {
+            for (int c = 0; c < n; c++) {
+                if(board[r][c] == 2)
+                    board[r][c] = 0;
+                else if (board[r][c] == 3)
+                    board[r][c] = 1;
+            }
+        }
+
+    }
+}

GetMinMax.java

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+//Time Complexity : O(n)
+//Space Complexity : O(1)
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class GetMinMax {
+    public ArrayList<Integer> getMinMax(int[] arr) {
+        int n = arr.length;
+        int min, max;
+        int i;
+
+        if (n % 2 == 0) {
+            if (arr[0] < arr[1]) {
+                min = arr[0];
+                max = arr[1];
+            } else {
+                min = arr[1];
+                max = arr[0];
+            }
+            i = 2;
+        } else {
+            min = max = arr[0];
+            i = 1;
+        }
+
+        while (i < n - 1) {
+            if (arr[i] < arr[i + 1]) {
+                min = Math.min(min, arr[i]);
+                max = Math.max(max, arr[i + 1]);
+            } else {
+                min = Math.min(min, arr[i + 1]);
+                max = Math.max(max, arr[i]);
+            }
+            i += 2;
+        }
+
+        return new ArrayList<>(List.of(min, max));
+    }
+}