HackerRank içerisinde bulunan “Mars Exploration” sorusunun açıklaması ve çözümü. Bu soruda size verilen bir “SOS” string’inin orijinalinden kaç adet farklı karakter barındırdığını bulmanız isteniyor.

► HackerRank – Mars Exploration: https://www.hackerrank.com/challenges/mars-exploration/problem

► Problem açıklaması:

A space explorer’s ship crashed on Mars! They send a series of SOS messages to Earth for help.

Letters in some of the SOS messages are altered by cosmic radiation during transmission. Given the signal received by Earth as a string, s, determine how many letters of the SOS message have been changed by radiation.

Example

s = “SOSTOT”

The original message was SOSSOS. Two of the message’s characters were changed in transit.

Function Description

Complete the marsExploration function in the editor below.

marsExploration has the following parameter(s):

string s: the string as received on Earth

Returns

int: the number of letters changed during transmission

Sample Input 0

SOSSPSSQSSOR

Sample Output 0

3

Explanation 0

= SOSSPSSQSSOR, and signal length s = |12|. They sent 4 SOS messages (i.e.: ).

Expected signal: SOSSOSSOSSOS

Recieved signal: SOSSPSSQSSOR

Difference: X X X

Sample Input 1

SOSSOT

Sample Output 1

1

Explanation 1

s = SOSSOT, and signal length 6. They sent 2 SOS messages (i.e.: ).

Expected Signal: SOSSOS

Received Signal: SOSSOT

Difference: X

Sample Input 2

SOSSOSSOS

Sample Output 2

0

Explanation 2

Since no character is altered, return 0