[hackerrank] alternating characters

num_of_deletion.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_STR_LEN 100000

int num_of_deletion(const char const * s) {
  if ( s == NULL || 0 == strlen(s) || MAX_STR_LEN < strlen(s) )
    return 0;
  int len = strlen(s);
  int i = 0, cnt = 0;
  char prev = *(s + 0);
  for ( i = 1; i < len; ++i ) {
    if ( prev == *(s + i) )
      cnt += 1;
    else
      prev = *(s + i);
  }
  return cnt;
}


int main()  {
  int num_of_test_case = 0;
  fscanf(stdin, "%d", &num_of_test_case);
  int* test_cases = (int*) malloc(sizeof(int) * num_of_test_case);
  int i = 0;
  for ( i = 0; i < num_of_test_case; ++i )  {
    char s[MAX_STR_LEN + 1];
    memset(s, '\0', MAX_STR_LEN + 1);
    fscanf(stdin, "%s", s);
    printf("%d\n", num_of_deletion(s));
  }
}

num_of_deletion.py

import sys


def num_of_deletion(s):
  cnt = 0
  prev = s[0]
  for c in s[1:]:
    if c == prev:
      cnt += 1
    else:
      prev = c
  return cnt

if __name__ == '__main__':
  inp = []
  for line in sys.stdin:
    inp.append(line.strip())
  for i in inp[1:]:
    print num_of_deletion(i)

NumOfDeletion.java

import java.util.Scanner;


public class Test {
  public static int numOfDeletion(final String s) {
    int cnt = 0;
    char prev = s.charAt(0);
    for ( int i = 1; i < s.length(); ++i )  {
      char c = s.charAt(i);
      if ( prev == c )
        cnt += 1;
      else
        prev = c;
    }
    return cnt;
  }

  public static void main(String[] args)  {
    Scanner sc = new Scanner(System.in);
    int numOfTestCases = Integer.parseInt(sc.nextLine());
    for ( int i = 0; i < numOfTestCases; ++i )  {
      System.out.println(numOfDeletion(sc.nextLine()));
    }
  }
}

NumOfDeletion.scala

// https://www.hackerrank.com/challenges/alternating-characters
object Solution {
  def numOfDeletion(s: String): Int = {
    var cnt: Int = 0
    var prev: Char = s(0)
    for ( c <- s.drop(1) )  {
      if ( prev == c )
        cnt += 1
      else
        prev = c
    }
    cnt
  }
  def main(args: Array[String]) {
    val inp = io.Source.stdin.getLines.drop(1)
    for (i <- inp) println(numOfDeletion(i))
  }
}