771_Jewels_and_Stones and 804_Unique_Morse_Code_Words

Author: qiyuangong

README.md

@@ -132,6 +132,8 @@ Remember solutions are only solutions to given problems. If you want full study
 | 443 | [String Compression](https://leetcode.com/problems/string-compression/description/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/443_String_Compression.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/443_String_Compression.java) | Maintain curr, read, write and anchor (start of this char). |
 | 453 | [Number of Segments in a String](https://leetcode.com/problems/minimum-moves-to-equal-array-elements/description/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/453_Minimum_Moves_to_Equal_Array_Elements.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/453_Minimum_Moves_to_Equal_Array_Elements.java) | Each move is equal to minus one element in array, so the answer is the sum of all elements after minus min. |
 | 463 | [Island Perimeter](https://leetcode.com/problems/island-perimeter/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/463_Island_Perimeter.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/463_Island_Perimeter.java) | math, find the area, actual number, then find the digit |
+| 771 | [Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/description/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/771_Jewels_and_Stones.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/771_Jewels_and_Stones.java) | Count given char in string. Hash or table. [Oneline](https://leetcode.com/problems/jewels-and-stones/discuss/113574/1-liners-PythonJavaRuby) |
+| 804 | [Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words/description/) | [Python](https://github.com/qiyuangong/leetcode/blob/master/python/771_Jewels_and_Stones.py) [Java](https://github.com/qiyuangong/leetcode/blob/master/java/771_Jewels_and_Stones.java) | String, Hash and Set. Set is recommended. |
 
 | # | To Understand |
 |---| ----- |

java/771_Jewels_and_Stones.java

@@ -0,0 +1,17 @@
+import java.util.HashSet;
+
+class Solution {
+    public int numJewelsInStones(String J, String S) {
+        int result = 0;
+        HashSet jHash = new HashSet<>();
+        for (int j = 0; j < J.length(); j++) {
+            jHash.add(J.charAt(j));
+        }
+        for (int s = 0; s < S.length(); s++) {
+            if (jHash.contains(S.charAt(s))) {
+                result++;
+            }
+        }
+        return result;
+    }
+}

java/804_Unique_Morse_Code_Words.java

@@ -0,0 +1,19 @@
+class Solution {
+    // https://leetcode.com/problems/unique-morse-code-words/solution/
+    public int uniqueMorseRepresentations(String[] words) {
+        String[] MORSE = new String[]{".-","-...","-.-.","-..",".","..-.","--.",
+                         "....","..",".---","-.-",".-..","--","-.",
+                         "---",".--.","--.-",".-.","...","-","..-",
+                         "...-",".--","-..-","-.--","--.."};
+
+        Set<String> seen = new HashSet();
+        for (String word: words) {
+            StringBuilder code = new StringBuilder();
+            for (char c: word.toCharArray())
+                code.append(MORSE[c - 'a']);
+            seen.add(code.toString());
+        }
+
+        return seen.size();
+    }
+}

python/771_Jewels_and_Stones.py

@@ -0,0 +1,15 @@
+class Solution(object):
+    def numJewelsInStones(self, J, S):
+        """
+        :type J: str
+        :type S: str
+        :rtype: int
+        """
+        if len(J) == 0 or len(S) == 0:
+            return 0
+        j_set = set(J)
+        ans = 0
+        for c in S:
+            if c in j_set:
+                ans += 1
+        return ans

python/804_Unique_Morse_Code_Words.py

@@ -0,0 +1,24 @@
+Morse_tab = [".-","-...","-.-.",
+             "-..",".","..-.","--.","....",
+             "..",".---","-.-",".-..","--",
+             "-.","---",".--.","--.-",".-.",
+             "...","-","..-","...-",".--",
+             "-..-","-.--","--.."]
+
+class Solution(object):
+    # https://leetcode.com/problems/unique-morse-code-words/solution/
+    def uniqueMorseRepresentations(self, words):
+        """
+        :type words: List[str]
+        :rtype: int
+        """
+        if len(words) == 0:
+            return 0
+        ans_set = set()
+        for word in words:
+            morsed = ""
+            for c in word:
+                morsed += Morse_tab[ord(c) - ord('a')]
+            
+            ans_set.add(morsed)
+        return len(ans_set)