New Problem Solution - "Ransom Note"

Author: haoel

README.md

@@ -13,6 +13,7 @@ LeetCode
 |386|[Lexicographical Numbers](https://leetcode.com/problems/lexicographical-numbers/) | [C++](./algorithms/cpp/lexicographicalNumbers/LexicographicalNumbers.cpp)|Medium|
 |385|[Mini Parser](https://leetcode.com/problems/mini-parser/) | [C++](./algorithms/cpp/miniParser/MiniParser.cpp)|Medium|
 |384|[Shuffle an Array](https://leetcode.com/problems/shuffle-an-array/) | [C++](./algorithms/cpp/shuffleAnArray/ShuffleAnArray.cpp)|Medium|
+|383|[Ransom Note](https://leetcode.com/problems/ransom-note/) | [C++](./algorithms/cpp/ransomNote/RansomNote.cpp)|Easy|
 |377|[Combination Sum IV](https://leetcode.com/problems/combination-sum-iv/) | [C++](./algorithms/cpp/combinationSumIV/combinationSumIV.cpp)|Medium|
 |376|[Wiggle Subsequence](https://leetcode.com/problems/wiggle-subsequence/) | [C++](./algorithms/cpp/wiggleSubsequence/wiggleSubsequence.cpp)|Medium|
 |350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/) | [C++](./algorithms/cpp/intersectionOfTwoArraysII/intersectionOfTwoArraysII.cpp)|Easy|

algorithms/cpp/ransomNote/RansomNote.cpp

@@ -0,0 +1,38 @@
+// Source : https://leetcode.com/problems/ransom-note/
+// Author : Hao Chen
+// Date   : 2016-08-24
+
+/*************************************************************************************** 
+ *
+ * 
Given
 an 
arbitrary
 ransom
 note
 string 
and 
another 
string 
containing 
+ * 
letters from
 all 
the 
magazines,
 write 
a 
function 
that 
will 
return 
true 
+ * 
if 
the 
ransom 

+ * note 
can 
be 
constructed 
from 
the 
magazines ; 
otherwise, 
it 
will 
return 
+ * 
false. 


+ * 
+ * Each 
letter
 in
 the
 magazine 
string 
can
 only 
be
 used 
once
 in
 your 
+ * 
ransom
 note.
+ * 
+ * Note:
+ * You may assume that both strings contain only lowercase letters.
+ * 
+ * canConstruct("a", "b") -> false
+ * canConstruct("aa", "ab") -> false
+ * canConstruct("aa", "aab") -> true
+ ***************************************************************************************/
+
+class Solution {
+public:
+    bool canConstruct(string ransomNote, string magazine) {
+        unordered_map<char, int> m;
+        for(int i=0; i<magazine.size(); i++) {
+            m[magazine[i]]++;
+        }
+        for (int i=0; i<ransomNote.size(); i++) {
+            char c = ransomNote[i];
+            if (m[c] <=0 ) return false;
+            m[c]--;
+        }
+        return true;
+    }
+};