optimized game of life

sherxon · Jun 29, 2018 · 8870c55 · 8870c55
1 parent 0c66245
commit 8870c55
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Showing 2 changed files with 40 additions and 18 deletions.
diff --git a/src/problems/medium/ContainerWithMostWater.java b/src/problems/medium/ContainerWithMostWater.java
@@ -1,5 +1,7 @@
 package problems.medium;
 
+import java.util.*;
+
 /**
  * Why Did you create this class? what does it do?
  */

diff --git a/src/problems/medium/GameofLife.java b/src/problems/medium/GameofLife.java
@@ -4,37 +4,57 @@
  * Created by sherxon on 1/28/17.
  */
 public class GameofLife {
-    static void gameOfLife(int[][] a) {
+    public void gameOfLife(int[][] a) {
+        if (a == null || a.length == 0)
+            return;
         for (int i = 0; i < a.length; i++) {
             for (int j = 0; j < a[i].length; j++) {
-                int al = getAliveN(a, i, j);
-                if (a[i][j] == 1 && (al < 2 || al > 3))
+                int count = count(a, i, j);
+                if (isAlive(a, i, j) && count < 2)
                     a[i][j] = -1;
-                else if (a[i][j] == 0 && al == 3)
-                    a[i][j] = 2;
+                else if (isAlive(a, i, j) && count > 3)
+                    a[i][j] = -1;
+                else if (isAlive(a, i, j))
+                    a[i][j] = 1;
+                else if (!isAlive(a, i, j) && count == 3)
+                    a[i][j] = -2;
             }
         }
         for (int i = 0; i < a.length; i++) {
             for (int j = 0; j < a[i].length; j++) {
-                if (a[i][j] == -1) a[i][j] = 0;
-                else if (a[i][j] == 2) a[i][j] = 1;
+                if (a[i][j] == -1)
+                    a[i][j] = 0;
+                else if (a[i][j] == -2)
+                    a[i][j] = 1;
             }
         }
 
     }
 
-    private static int getAliveN(int[][] a, int i, int j) {
-        int count = 0;
-        if (j < a[i].length - 1 && (a[i][j + 1] == 1 || a[i][j + 1] == -1)) count++;
-        if (j > 0 && (a[i][j - 1] == 1 || a[i][j - 1] == -1)) count++;
-        if (i > 0 && (a[i - 1][j] == 1 || a[i - 1][j] == -1)) count++;
-        if (i < a.length - 1 && (a[i + 1][j] == 1 || a[i + 1][j] == -1)) count++;
-
-        if (i < a.length - 1 && j < a[i].length - 1 && (a[i + 1][j + 1] == 1 || a[i + 1][j + 1] == -1)) count++;
-        if (i < a.length - 1 && j > 0 && (a[i + 1][j - 1] == 1 || a[i + 1][j - 1] == -1)) count++;
-        if (i > 0 && j > 0 && (a[i - 1][j - 1] == 1 || a[i - 1][j - 1] == -1)) count++;
-        if (i > 0 && j < a[i].length - 1 && (a[i - 1][j + 1] == 1 || a[i - 1][j + 1] == -1)) count++;
+    boolean isAlive(int[][] a, int i, int j) {
+        if (i < 0 || j < 0 || i >= a.length || j >= a[i].length)
+            return false;
+        return a[i][j] == 1 || a[i][j] == -1;
+    }
 
+    int count(int[][] a, int i, int j) {
+        int count = 0;
+        if (isAlive(a, i - 1, j - 1))
+            count++;
+        if (isAlive(a, i - 1, j))
+            count++;
+        if (isAlive(a, i - 1, j + 1))
+            count++;
+        if (isAlive(a, i, j - 1))
+            count++;
+        if (isAlive(a, i, j + 1))
+            count++;
+        if (isAlive(a, i + 1, j - 1))
+            count++;
+        if (isAlive(a, i + 1, j))
+            count++;
+        if (isAlive(a, i + 1, j + 1))
+            count++;
         return count;
     }
 }