Some Useful JAVA String technique

28 Oct 2021 in Algorithms

1. When Concatenating String…

• Do use Character array or String Builder
• Do not use str +=str, The time complexity for this method is O(n^2) !

1. Character array : O(n)

   String a ="BoilingPoint";
   char[] chars = a.toCharArray();
   

2. StringBuilder : O(n)

   StringBuilder str = new StringBuilder();
   for(int i=0;i<n;i++){
       str.append("hello");
   }
   String s = str.toString();
   

2. When Storing Substring of s that contains characters…

• Map can be a great solution

• According to ASCII table, 65~90 : Capital Letters, 97~122 : Lowercase Letters.

  This method shows better performance,

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