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  1. Mars Exploration
  2. Discussions

Mars Exploration

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215 Discussions

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  • cbiggin
     + 0 comments

    swift

    func marsExploration(s: String) -> Int {
    var changed = 0
    for (index, c) in s.enumerated() {
        switch index % 3 {
            case 0, 2:
               if c != "S" {
                    changed = changed + 1
               }
            case 1:
                if c != "O" {
                    changed = changed + 1
               }
            default:
                break
        }
    }
    return changed
}

  • juanp766
     + 0 comments

    We need to keep track of the position since an S could also be changed for an O. So just counting isn't enough

      public static int marsExploration(String s) {
        
        int counter = 0;
        int position = 1;
        for(int i = 0; i < s.length(); i++){            
            System.out.println(position);
            
            if((position == 1 || position == 3) && s.charAt(i) != 'S') {
            counter++;
            }else if(position == 2 && s.charAt(i) != 'O'){
            counter++;
            }   
            
            if(position == 3){
                position = 1;
            }else{
                position++;
            }                                                                                                                                            
        }
        
        return counter;
    }

  • shakeebahmed336
     + 0 comments

    Here's my python code:

    def marsExploration(s):
    sos = "SOS" * (len(s)//3)
    changed = 0
    for index, item in enumerate(s):
        if item != sos[index]:
            changed += 1
    return changed

  • karrisatyalaxmi1
     + 0 comments

    Herw my java code:

    public static int marsExploration(String s) {
 int    count = 0;
char[] ch = s.toCharArray();
for(int i=0; i<s.length(); i+=3) {
    if(ch[i] !='S')
        count++;
    if(ch[i+1] !='O')
        count++;
    if(ch[i+2] !='S')
       count++;
}
return count;
}

  • victor_reial
     + 0 comments

    Rust best solution

    If you’re looking for solutions to the 3-month preparation kit in either Python or Rust, you can find them below: my solutions 

    pub fn mars_exploration(s: &str) -> i32 {
    //Time complexity: O(n)
    //Space complexity (ignoring input): O(1)
    let sos_array: Vec<_> = "SOS".chars().collect();
    let mut changed_letters = 0;
    for (index, letter) in s.char_indices(){
        if letter != sos_array[index%3]{
            changed_letters += 1;
        }
    }
    changed_letters
}