refactor 67

fishercoder1534 · fishercoder1534 · commit e9f7a4b1941e · 2018-01-30T07:27:41.000-08:00
diff --git a/src/main/java/com/fishercoder/solutions/_67.java b/src/main/java/com/fishercoder/solutions/_67.java
@@ -2,6 +2,7 @@
 
 /**
  * 67. Add Binary
+ *
  * Given two binary strings, return their sum (also a binary string).
  * For example,
  * a = "11"
@@ -10,95 +11,33 @@
  */
 
 public class _67 {
-    //then I turned to Discuss, this post is concise: https://discuss.leetcode.com/topic/13698/short-ac-solution-in-java-with-explanation
-    //Tricks and things learned that could be learned:
-    //1. use StringBuilder.reverse() function! Nice!
-    //2. if a numeric number is represented/stored in String, how to get its value: use Character.getNumericValue(s.charAt(i))
-    //3. directly adding/subtracting chars will end up working with their ASCII numbers, e.g. chars[0] = 'a', chars[1] = 'b', then chars[0] + chars[1] will become 195
+  public static class Solution1 {
+    /**
+     * credit: https://discuss.leetcode.com/topic/13698/short-ac-solution-in-java-with-explanation
+     * 1. use StringBuilder.reverse() function! Nice!
+     * 2. if a numeric number is represented/stored in String, how to get its value: use Character.getNumericValue(s.charAt(i))
+     * 3. directly adding/subtracting chars will end up working with their ASCII numbers, e.g. chars[0] = 'a', chars[1] = 'b', then chars[0] + chars[1] will become 195.
+     */
     public String addBinary(String a, String b) {
-        int carry = 0;
-        int i = a.length() - 1;
-        int j = b.length() - 1;
-        StringBuilder sb = new StringBuilder();
-        while (i >= 0 || j >= 0) {
-            int sum = carry;
-            if (i >= 0) {
-                sum += a.charAt(i--) - '0';
-            }
-            if (j >= 0) {
-                sum += b.charAt(j--) - '0';
-            }
-            sb.append(sum % 2);
-            carry = sum / 2;
+      int carry = 0;
+      int i = a.length() - 1;
+      int j = b.length() - 1;
+      StringBuilder sb = new StringBuilder();
+      while (i >= 0 || j >= 0) {
+        int sum = carry;
+        if (i >= 0) {
+          sum += a.charAt(i--) - '0';
         }
-        if (carry != 0) {
-            sb.append(carry);
+        if (j >= 0) {
+          sum += b.charAt(j--) - '0';
         }
-        return sb.reverse().toString();
-    }
-
-    //my original lengthy but AC'ed solution
-    public String addBinary_my_original_accepted_but_lengthy_solution(String a, String b) {
-        char[] longer = (a.length() >= b.length()) ? a.toCharArray() : b.toCharArray();
-        char[] shorter = (a.length() < b.length()) ? a.toCharArray() : b.toCharArray();
-        //at the maximum, the result length will be Math.max(a.length, b.length)+1;
-        //let's use Math.max() as the length first, if the most signifant bits add up to a carry, then we'll add one more bit
-        char[] result = new char[longer.length];
-        boolean carry = false;
-        int i = longer.length - 1;
-        int j = shorter.length - 1;
-        System.out.println(Character.getNumericValue(longer[i]) + Character.getNumericValue(shorter[j]));
-        System.out.println((int) longer[i] + (int) shorter[j]);
-        System.out.println(longer[i] + shorter[j]);
-        System.out.println('a' + 'b');
-        for (; i >= 0 || j >= 0; i--, j--) {
-            if (j < 0 && i >= 0) {
-                if (carry) {
-                    if (Character.getNumericValue(longer[i]) + 1 == 2) {
-                        result[i] = '0';
-                        carry = true;
-                    } else {
-                        result[i] = '1';
-                        carry = false;
-                    }
-                } else {
-                    for (int k = i; k >= 0; k--) {
-                        result[k] = longer[k];
-                    }
-                    return new String(result);
-                }
-            } else if (Character.getNumericValue(longer[i]) + Character.getNumericValue(shorter[j]) == 2) {
-                if (carry) {
-                    result[i] = '1';
-                } else {
-                    result[i] = '0';
-                }
-                carry = true;
-            } else if (Character.getNumericValue(longer[i]) + Character.getNumericValue(shorter[j]) == 1) {
-                if (carry) {
-                    result[i] = '0';
-                    carry = true;
-                } else {
-                    result[i] = '1';
-                    carry = false;
-                }
-            } else if (Character.getNumericValue(longer[i]) + Character.getNumericValue(shorter[j]) == 0) {
-                if (carry) {
-                    result[i] = '1';
-                } else {
-                    result[i] = '0';
-                }
-                carry = false;
-            }
-        }
-        if (carry) {
-            char[] newResult = new char[longer.length + 1];
-            newResult[0] = '1';
-            for (int k = 0; k < result.length; k++) {
-                newResult[k + 1] = result[k];
-            }
-            return new String(newResult);
-        }
-        return new String(result);
+        sb.append(sum % 2);
+        carry = sum / 2;
+      }
+      if (carry != 0) {
+        sb.append(carry);
+      }
+      return sb.reverse().toString();
     }
+  }
 }
diff --git a/src/test/java/com/fishercoder/_67Test.java b/src/test/java/com/fishercoder/_67Test.java
@@ -1,81 +1,21 @@
 package com.fishercoder;
 
 import com.fishercoder.solutions._67;
-
-import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
 import static junit.framework.Assert.assertEquals;
 
-/**
- * Created by fishercoder on 1/8/17.
- */
 public class _67Test {
-    private static _67 test;
-    private static String expected;
-    private static String actual;
-    private static String a;
-    private static String b;
-
-    @BeforeClass
-    public static void setup() {
-        test = new _67();
-        expected = new String();
-        actual = new String();
-        a = new String();
-        b = new String();
-    }
-
-    @Before
-    public void setupForEachTest() {
-        expected = "";
-        actual = "";
-        a = "";
-        b = "";
-    }
-
-    @Test
-    public void test1() {
-
-        a = "0";
-        b = "0";
-        expected = "0";
-        actual = test.addBinary(a, b);
-        assertEquals(expected, actual);
-
-    }
-
-    @Test
-    public void test2() {
-
-        a = "11";
-        b = "1";
-        expected = "100";
-        actual = test.addBinary(a, b);
-        assertEquals(expected, actual);
-
-    }
-
-    @Test
-    public void test3() {
-
-        a = "100";
-        b = "110010";
-        expected = "110110";
-        actual = test.addBinary(a, b);
-        assertEquals(expected, actual);
-
-    }
-
-    @Test
-    public void test4() {
+  private static _67.Solution1 solution1;
 
-        a = "101111";
-        b = "10";
-        expected = "110001";
-        actual = test.addBinary(a, b);
-        assertEquals(expected, actual);
+  @BeforeClass
+  public static void setup() {
+    solution1 = new _67.Solution1();
+  }
 
-    }
+  @Test
+  public void test1() {
+    assertEquals("100", solution1.addBinary("11", "1"));
+  }
 }
