Wednesday, November 5, 2014

Number of characters appearing in all given strings

Given a set of n strings, we have to write a program to find out the number of characters appearing in all the strings.

For example consider the following strings
{"India", "China", "United states"}, the letters {a,i,n} appear in all the strings.

Let us think of the following solution.
  • We first add all the characters in the first string to a set. 
  • For each string we do the following.
    • For each letter in the set, we check if it can be found the string.
    • If it is not found, we delete it from the set
  • Finally the set contains only the elements which appear in all the given strings.
Here is the C++ code which implements the above approach. For simplicity this program assumes that all the strings contains lower case alphabets only.