[LeetCode] Ransom Note
This code takes about 300ms.
A very typical application of hash maps. Since I am now learning Java, I code in Java. The following code uses toCharArray() and getOrDefault(), which are learnt from this post.
This version is much faster, about 13ms.
In fact, arrays can be used to replace hash maps since the test cases of this problem only contan the 26 English letters. A array-version solution can be found here and is rewritten below.