array-2

FindAllNum.java

@@ -0,0 +1,21 @@
+import java.util.*;
+
+public class FindAllNum {
+    public List<Integer> findAllNum1(int[] nums) {
+        List<Integer> ans = new ArrayList<>();
+
+        for (int i=0; i<nums.length; i++){
+            int curr = Math.abs(nums[i]);
+            int numAtIdx = nums[curr-1];
+            if (numAtIdx >0) {
+                nums[curr-1] = nums[curr-1]* -1;
+            } 
+        }
+        for (int i=0; i<nums.length; i++){
+            if (nums[i] > 0) {
+                ans.add(i+1);
+            }
+        }
+        return ans;
+    }
+}

FindAllNum1.java

@@ -0,0 +1,20 @@
+import java.util.*;
+
+public class FindAllNum1 {
+    public List<Integer> findAllNum1(int[] nums) {
+        List<Integer> ans = new ArrayList<>();
+        HashSet<Integer> hS = new HashSet<>();
+
+        for (int i = 0; i < nums.length; i++) {
+            if (!hS.contains(nums[i])) {
+                hS.add(nums[i]);
+            }
+        }
+        for (int i = 0; i < nums.length; i++) {
+            if (!hS.contains(i + 1)) {
+                ans.add(i + 1);
+            }
+        }
+        return ans;
+    }
+}

GameofLife.java

@@ -0,0 +1,47 @@
+public class GameofLife {
+    // 1 -> 0 = 5
+    // 0 -> 1 = -1
+
+    public void gameOfLife(int[][] m) {
+        int row = board.length;
+        int col = board[0].length;
+        for (int i=0; i<row; i++){
+            for (int j=0; j<col; j++){
+                int count = lifeCount(board, i, j);
+                if (board[i][j] == 1 && (count <2 || count >3)) {
+                    board[i][j] = -1;
+                }  else if (board[i][j] == 0 && count ==3) {
+                    board[i][j] = 2;
+                }
+            }
+        }
+        //if -1 => change it to 0
+        //if 2 => change to 1;
+        for (int i=0; i<row; i++){
+            for (int j=0; j<col; j++){
+                if (board[i][j] == -1) {
+                    board[i][j] = 0;
+                }  else if (board[i][j] == 2) {
+                    board[i][j] = 1;
+                }
+            }
+        }        
+    }
+    private int lifeCount(int[][] board, int row, int col) {
+        int[][] dirs = {{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1}};
+        int rows = board.length;
+        int cols = board[0].length;
+        int count =0;
+        for (int[] dir: dirs) {
+            int adjRow = row+dir[0];
+            int adjCol = col+dir[1];
+
+            if ((adjRow>=0 && adjRow<rows) &&(adjCol>=0 && adjCol<cols)){
+                if (board[adjRow][adjCol] == 1 || board[adjRow][adjCol] == -1) {
+                    count++;
+                }
+            }
+        }
+        return count;
+    }
+}

MaxMin.java

@@ -0,0 +1,22 @@
+import java.util.*;
+
+public class MaxMin {
+
+    // nums = [-3,-5,5,2,3,7];
+
+    public List<Integer> maxMin(int[] nums) {
+        ArrayList<Integer> sortedArr = new ArrayList<>();
+        for (int num : arr) {
+            sortedArr.add(num);
+        }
+
+        // Sort ArrayList
+        Collections.sort(sortedArr);
+
+        ArrayList<Integer> result = new ArrayList<>();
+        result.add(sortedArr.get(0));               
+        result.add(sortedArr.get(sortedArr.size() - 1)); 
+
+        return result;
+    }
+}