alternatingCharacters.js

'use strict';

const fs = require('fs');

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', _ => {
    inputString = inputString.replace(/\s*$/, '')
        .split('\n')
        .map(str => str.replace(/\s*$/, ''));

    main();
});

function readLine() {
    return inputString[currentLine++];
}

// Complete the alternatingCharacters function below.
function alternatingCharacters(s) {
    let input =s.split('');
    let i;
    let n=input.length;
    let counter=0;
    for(i=0;i<n-1;i++){
        if(input[i]==input[i+1]){
            counter++;
        }
    }
    return counter;

}

function main() {
    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

    const q = parseInt(readLine(), 10);

    for (let qItr = 0; qItr < q; qItr++) {
        const s = readLine();

        let result = alternatingCharacters(s);

        ws.write(result + "\n");
    }

    ws.end();
}