refactor 207

fishercoder1534 · fishercoder1534 · commit 4068e92f53e2 · 2018-09-17T07:32:38.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_207.java b/src/main/java/com/fishercoder/solutions/_207.java
@@ -4,7 +4,10 @@
 import java.util.Iterator;
 import java.util.Set;
 
-/**There are a total of n courses you have to take, labeled from 0 to n - 1.
+/**
+ * 207. Course Schedule
+ *
+ * There are a total of n courses you have to take, labeled from 0 to n - 1.
  Some courses may have prerequisites, for example to take course 0 you have to first take course 1,
  which is expressed as a pair: [0,1]
  Given the total number of courses and a list of prerequisite pairs, is it possible for you to finish all courses?
@@ -27,44 +30,46 @@
  Hints:
  This problem is equivalent to finding if a cycle exists in a directed graph. If a cycle exists, no topological ordering exists and therefore it will be impossible to take all courses.
  Topological Sort via DFS - A great video tutorial (21 minutes) on Coursera explaining the basic concepts of Topological Sort.
- Topological sort could also be done via BFS.*/
+ Topological sort could also be done via BFS.
+ */
 public class _207 {
 
-    public boolean canFinish(int numCourses, int[][] prerequisites) {
-        int[] indegree = new int[numCourses];
-        for (int[] prereq : prerequisites) {
-            indegree[prereq[0]]++;
-        }
-        Set<Integer> zeroDegree = new HashSet();
-        for (int i = 0; i < numCourses; i++) {
-            if (indegree[i] == 0) {
-                zeroDegree.add(i);
+    public static class Solution1 {
+        public boolean canFinish(int numCourses, int[][] prerequisites) {
+            int[] indegree = new int[numCourses];
+            for (int[] prereq : prerequisites) {
+                indegree[prereq[0]]++;
+            }
+            Set<Integer> zeroDegree = new HashSet();
+            for (int i = 0; i < numCourses; i++) {
+                if (indegree[i] == 0) {
+                    zeroDegree.add(i);
+                }
+            }
+            if (zeroDegree.isEmpty()) {
+                return false;
             }
-        }
-        if (zeroDegree.isEmpty()) {
-            return false;
-        }
 
-        while (!zeroDegree.isEmpty()) {
-            Iterator<Integer> it = zeroDegree.iterator();
-            int course = it.next();
-            zeroDegree.remove(course);
-            for (int[] prereq : prerequisites) {
-                if (prereq[1] == course) {
-                    indegree[prereq[0]]--;
-                    if (indegree[prereq[0]] == 0) {
-                        zeroDegree.add(prereq[0]);
+            while (!zeroDegree.isEmpty()) {
+                Iterator<Integer> it = zeroDegree.iterator();
+                int course = it.next();
+                zeroDegree.remove(course);
+                for (int[] prereq : prerequisites) {
+                    if (prereq[1] == course) {
+                        indegree[prereq[0]]--;
+                        if (indegree[prereq[0]] == 0) {
+                            zeroDegree.add(prereq[0]);
+                        }
                     }
                 }
             }
-        }
 
-        for (int i : indegree) {
-            if (i != 0) {
-                return false;
+            for (int i : indegree) {
+                if (i != 0) {
+                    return false;
+                }
             }
+            return true;
         }
-        return true;
     }
-
 }
diff --git a/src/test/java/com/fishercoder/_207Test.java b/src/test/java/com/fishercoder/_207Test.java
@@ -7,15 +7,15 @@
 import static junit.framework.Assert.assertEquals;
 
 public class _207Test {
-    private static _207 test;
+    private static _207.Solution1 test;
     private static boolean actual;
     private static boolean expected;
     private static int[][] prerequisites;
     private static int numCourses;
 
     @BeforeClass
     public static void setup() {
-        test = new _207();
+        test = new _207.Solution1();
     }
 
     @Test
