add 800

Author: fishercoder1534

README.md

@@ -25,6 +25,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |811|[Subdomain Visit Count](https://leetcode.com/problems/subdomain-visit-count/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_811.java) | O(n) | O(n) | |Easy| HashMap
 |806|[Number of Lines To Write String](https://leetcode.com/problems/number-of-lines-to-write-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_806.java) | O(n) | O(1) | |Easy|
 |804|[Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_804.java) | O(S) | O(S) | |Easy|
+|800|[Similar RGB Color](https://leetcode.com/problems/similar-rgb-color/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_800.java) | O(1) | O(1) | |Easy|
 |799|[Champagne Tower](https://leetcode.com/problems/champagne-tower/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_799.java) | O(r^2) or O(1) | O(r^2) or O(1) | |Medium|
 |796|[Rotate String](https://leetcode.com/problems/rotate-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_796.java) | O(n) | O(1) | |Easy|
 |791|[Custom Sort String](https://leetcode.com/problems/custom-sort-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_791.java) | O(n+m) | O(1) | |Medium|

src/main/java/com/fishercoder/solutions/_800.java

@@ -0,0 +1,84 @@
+package com.fishercoder.solutions;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * 800. Similar RGB Color
+
+ In the following, every capital letter represents some hexadecimal digit from 0 to f.
+
+ The red-green-blue color "#AABBCC" can be written as "#ABC" in shorthand.  For example, "#15c" is shorthand for the color "#1155cc".
+
+ Now, say the similarity between two colors "#ABCDEF" and "#UVWXYZ" is -(AB - UV)^2 - (CD - WX)^2 - (EF - YZ)^2.
+
+ Given the color "#ABCDEF", return a 7 character color that is most similar to #ABCDEF, and has a shorthand (that is, it can be represented as some "#XYZ"
+
+ Example 1:
+ Input: color = "#09f166"
+ Output: "#11ee66"
+ Explanation:
+ The similarity is -(0x09 - 0x11)^2 -(0xf1 - 0xee)^2 - (0x66 - 0x66)^2 = -64 -9 -0 = -73.
+ This is the highest among any shorthand color.
+
+ Note:
+
+ color is a string of length 7.
+ color is a valid RGB color: for i > 0, color[i] is a hexadecimal digit from 0 to f
+ Any answer which has the same (highest) similarity as the best answer will be accepted.
+ All inputs and outputs should use lowercase letters, and the output is 7 characters.
+
+ */
+public class _800 {
+  public static class Solution1 {
+    public String similarRGB(String color) {
+      List<String> allShortHandCombinations = computeAllShorthandCombinations();
+      int minSimilarity = Integer.MIN_VALUE;
+      String result = "";
+      for (String candidate : allShortHandCombinations) {
+        int similarity = computeSimilarity(candidate, color);
+        if (similarity > minSimilarity) {
+          result = candidate;
+          minSimilarity = similarity;
+        }
+      }
+      return result;
+    }
+
+    private int computeSimilarity(String candidate, String color) {
+      return -(Integer.parseInt(candidate.substring(1, 3), 16) - Integer.parseInt(
+          color.substring(1, 3), 16)) * (Integer.parseInt(candidate.substring(1, 3), 16)
+          - Integer.parseInt(color.substring(1, 3), 16))
+          - (Integer.parseInt(candidate.substring(3, 5), 16) - Integer.parseInt(
+          color.substring(3, 5), 16)) * (Integer.parseInt(candidate.substring(3, 5), 16)
+          - Integer.parseInt(color.substring(3, 5), 16))
+          - (Integer.parseInt(candidate.substring(5, 7), 16) - Integer.parseInt(
+          color.substring(5, 7), 16)) * (Integer.parseInt(candidate.substring(5, 7), 16)
+          - Integer.parseInt(color.substring(5, 7), 16));
+    }
+
+    private List<String> computeAllShorthandCombinations() {
+      List<String> result = new ArrayList<>();
+      List<Character> hexNumber = new ArrayList<>(
+          Arrays.asList('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',
+              'f'));
+      for (int i = 0; i < hexNumber.size(); i++) {
+        for (int j = 0; j < hexNumber.size(); j++) {
+          for (int k = 0; k < hexNumber.size(); k++) {
+            StringBuilder sb = new StringBuilder();
+            sb.append("#");
+            sb.append(hexNumber.get(i));
+            sb.append(hexNumber.get(i));
+            sb.append(hexNumber.get(j));
+            sb.append(hexNumber.get(j));
+            sb.append(hexNumber.get(k));
+            sb.append(hexNumber.get(k));
+            result.add(sb.toString());
+          }
+        }
+      }
+      return result;
+    }
+  }
+}

src/test/java/com/fishercoder/_800Test.java

@@ -0,0 +1,21 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._800;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _800Test {
+  private static _800.Solution1 solution1;
+
+  @BeforeClass
+  public static void setup() {
+    solution1 = new _800.Solution1();
+  }
+
+  @Test
+  public void test1() {
+    assertEquals("#11ee66", solution1.similarRGB("#09f166"));
+  }
+}