refactor 447

fishercoder1534 · fishercoder1534 · commit 8dbd0abaca08 · 2019-04-10T07:59:41.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_447.java b/src/main/java/com/fishercoder/solutions/_447.java
@@ -3,9 +3,15 @@
 import java.util.HashMap;
 import java.util.Map;
 
-/**Given n points in the plane that are all pairwise distinct, a "boomerang" is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple matters).
-
- Find the number of boomerangs. You may assume that n will be at most 500 and coordinates of points are all in the range [-10000, 10000] (inclusive).
+/**
+ * 447. Number of Boomerangs
+ *
+ * Given n points in the plane that are all pairwise distinct,
+ * a "boomerang" is a tuple of points (i, j, k) such that the distance
+ * between i and j equals the distance between i and k (the order of the tuple matters).
+ *
+ * Find the number of boomerangs.
+ * You may assume that n will be at most 500 and coordinates of points are all in the range [-10000, 10000] (inclusive).
 
  Example:
  Input:
@@ -17,57 +23,47 @@
  Explanation:
  The two boomerangs are [[1,0],[0,0],[2,0]] and [[1,0],[2,0],[0,0]]*/
 public class _447 {
-    /**Looked at these two posts: https://discuss.leetcode.com/topic/66587/clean-java-solution-o-n-2-166ms and 
-     * https://discuss.leetcode.com/topic/66521/share-my-straightforward-solution-with-hashmap-o-n-2, basically,
-     * have a HashMap, key is the distance, value is the number of points that are this distance apart to this point.
-     * Note: we clear up this map every time after we traverse one point with the rest of the other points.
-     * 
-     * Time complexity: O(n^2)
-     * Space complexity: O(n)*/
 
-    public int numberOfBoomerangs(int[][] points) {
-        int result = 0;
-        if (points == null || points.length == 0 || points[0].length == 0) {
-            return result;
-        }
-        int totalPts = points.length;
-        Map<Long, Integer> map = new HashMap();
-        for (int i = 0; i < totalPts; i++) {
-            for (int j = 0; j < totalPts; j++) {
-                if (i == j) {
-                    continue;
-                }
-                long d = calcDistance(points[i], points[j]);
-                map.put(d, map.getOrDefault(d, 0) + 1);
+    public static class Solution1 {
+        /**
+         * Looked at these two posts: https://discuss.leetcode.com/topic/66587/clean-java-solution-o-n-2-166ms and
+         * https://discuss.leetcode.com/topic/66521/share-my-straightforward-solution-with-hashmap-o-n-2, basically,
+         * have a HashMap, key is the distance, value is the number of points that are this distance apart to this point.
+         * Note: we clear up this map every time after we traverse one point with the rest of the other points.
+         * <p>
+         * Time complexity: O(n^2)
+         * Space complexity: O(n)
+         */
+
+        public int numberOfBoomerangs(int[][] points) {
+            int result = 0;
+            if (points == null || points.length == 0 || points[0].length == 0) {
+                return result;
             }
+            int totalPts = points.length;
+            Map<Long, Integer> map = new HashMap();
+            for (int i = 0; i < totalPts; i++) {
+                for (int j = 0; j < totalPts; j++) {
+                    if (i == j) {
+                        continue;
+                    }
+                    long d = calcDistance(points[i], points[j]);
+                    map.put(d, map.getOrDefault(d, 0) + 1);
+                }
 
-            for (int val : map.values()) {
-                result += val * (val - 1);
+                for (int val : map.values()) {
+                    result += val * (val - 1);
+                }
+                map.clear();
             }
-            map.clear();
+            return result;
         }
-        return result;
-    }
 
-    private long calcDistance(int[] p1, int[] p2) {
-        long x = p2[0] - p1[0];
-        long y = p2[1] - p1[1];
-        return x * x + y * y;
+        private long calcDistance(int[] p1, int[] p2) {
+            long x = p2[0] - p1[0];
+            long y = p2[1] - p1[1];
+            return x * x + y * y;
+        }
     }
 
-    public static void main(String... args) {
-        _447 test = new _447();
-        // int[][] points = new int[][]{
-        // {0,0},
-        // {1,0},
-        // {2,0},
-        // };
-
-        // [[3,6],[7,5],[3,5],[6,2],[9,1],[2,7],[0,9],[0,6],[2,6]], should return 10
-        int[][] points = new int[][] { { 3, 6 }, { 7, 5 }, { 3, 5 }, { 6, 2 }, { 9, 1 }, { 2, 7 },
-                { 0, 9 }, { 0, 6 }, { 2, 6 }, };
-
-        // [[0,0],[1,0],[-1,0],[0,1],[0,-1]] should return 20
-        System.out.println(test.numberOfBoomerangs(points));
-    }
-}
+}
diff --git a/src/test/java/com/fishercoder/_447Test.java b/src/test/java/com/fishercoder/_447Test.java
@@ -0,0 +1,44 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._447;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _447Test {
+    private static _447.Solution1 solution1;
+    private static int[][] points;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _447.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        points = new int[][]{
+                {0, 0},
+                {1, 0},
+                {2, 0},
+        };
+        assertEquals(2, solution1.numberOfBoomerangs(points));
+    }
+
+    @Test
+    public void test2() {
+        points = new int[][]{
+                {3, 6},
+                {7, 5},
+                {3, 5},
+                {6, 2},
+                {9, 1},
+                {2, 7},
+                {0, 9},
+                {0, 6},
+                {2, 6}
+        };
+        assertEquals(10, solution1.numberOfBoomerangs(points));
+    }
+
+}
