add one more solution for 893

fishercoder1534 · fishercoder1534 · commit 34b8696a2b77 · 2019-12-14T08:56:03.000-08:00
diff --git a/src/main/java/com/fishercoder/solutions/_893.java b/src/main/java/com/fishercoder/solutions/_893.java
@@ -1,9 +1,7 @@
 package com.fishercoder.solutions;
 
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -40,7 +38,7 @@
  * */
 public class _893 {
     public static class Solution1 {
-        /**my original solution, a bit length:
+        /**my original solution, a bit lengthy:
          * generate a unique signaure as key for each equivelant group and sum them up*/
         public int numSpecialEquivGroups(String[] A) {
             return Arrays.stream(A).map(this::getCommonKey).collect(Collectors.toSet()).size();
@@ -62,4 +60,29 @@ private String getCommonKey(String word) {
             return new StringBuffer().append(new String(evenIndexed)).append(new String(oddIndexed)).toString();
         }
     }
+
+    public static class Solution2 {
+        /**
+         * more concise solution: https://leetcode.com/problems/groups-of-special-equivalent-strings/discuss/163413/Java-Concise-Set-Solution
+         * but somehow a bit slower than mine: 12 ms vs 7ms
+         * I guess due to the problem constraint and this: "1 <= A[i].length <= 20" to have made this problem simpler
+         */
+        public int numSpecialEquivGroups(String[] A) {
+            Set<String> set = new HashSet<>();
+            for (String str : A) {
+                int[] odd = new int[26];
+                int[] even = new int[26];
+                for (int i = 0; i < str.length(); i++) {
+                    if (i % 2 == 0) {
+                        even[str.charAt(i) - 'a']++;
+                    } else {
+                        odd[str.charAt(i) - 'a']++;
+                    }
+                }
+                String key = Arrays.toString(even) + Arrays.toString(odd);
+                set.add(key);
+            }
+            return set.size();
+        }
+    }
 }
diff --git a/src/test/java/com/fishercoder/_893Test.java b/src/test/java/com/fishercoder/_893Test.java
@@ -8,25 +8,30 @@
 
 public class _893Test {
     private static _893.Solution1 solution1;
+    private static _893.Solution2 solution2;
 
     @BeforeClass
     public static void setup() {
         solution1 = new _893.Solution1();
+        solution2 = new _893.Solution2();
     }
 
     @Test
     public void test1() {
         assertEquals(3, solution1.numSpecialEquivGroups(new String[]{"abcd", "cdab", "cbad", "xyzz", "zzxy", "zzyx"}));
+        assertEquals(3, solution2.numSpecialEquivGroups(new String[]{"abcd", "cdab", "cbad", "xyzz", "zzxy", "zzyx"}));
     }
 
     @Test
     public void test2() {
         assertEquals(3, solution1.numSpecialEquivGroups(new String[]{"abc", "acb", "bac", "bca", "cab", "cba"}));
+        assertEquals(3, solution2.numSpecialEquivGroups(new String[]{"abc", "acb", "bac", "bca", "cab", "cba"}));
     }
 
     @Test
     public void test3() {
         assertEquals(1, solution1.numSpecialEquivGroups(new String[]{"abcd", "cdab", "adcb", "cbad"}));
+        assertEquals(1, solution2.numSpecialEquivGroups(new String[]{"abcd", "cdab", "adcb", "cbad"}));
     }
 
 }

Original file line number	Diff line number	Diff line change
`@@ -8,25 +8,30 @@`
`8`	`8`
`9`	`9`	`public class _893Test {`
`10`	`10`	`private static _893.Solution1 solution1;`
	`11`	`+ private static _893.Solution2 solution2;`
`11`	`12`
`12`	`13`	`@BeforeClass`
`13`	`14`	`public static void setup() {`
`14`	`15`	`solution1 = new _893.Solution1();`
	`16`	`+ solution2 = new _893.Solution2();`
`15`	`17`	`}`
`16`	`18`
`17`	`19`	`@Test`
`18`	`20`	`public void test1() {`
`19`	`21`	`assertEquals(3, solution1.numSpecialEquivGroups(new String[]{"abcd", "cdab", "cbad", "xyzz", "zzxy", "zzyx"}));`
	`22`	`+ assertEquals(3, solution2.numSpecialEquivGroups(new String[]{"abcd", "cdab", "cbad", "xyzz", "zzxy", "zzyx"}));`
`20`	`23`	`}`
`21`	`24`
`22`	`25`	`@Test`
`23`	`26`	`public void test2() {`
`24`	`27`	`assertEquals(3, solution1.numSpecialEquivGroups(new String[]{"abc", "acb", "bac", "bca", "cab", "cba"}));`
	`28`	`+ assertEquals(3, solution2.numSpecialEquivGroups(new String[]{"abc", "acb", "bac", "bca", "cab", "cba"}));`
`25`	`29`	`}`
`26`	`30`
`27`	`31`	`@Test`
`28`	`32`	`public void test3() {`
`29`	`33`	`assertEquals(1, solution1.numSpecialEquivGroups(new String[]{"abcd", "cdab", "adcb", "cbad"}));`
	`34`	`+ assertEquals(1, solution2.numSpecialEquivGroups(new String[]{"abcd", "cdab", "adcb", "cbad"}));`
`30`	`35`	`}`
`31`	`36`
`32`	`37`	`}`