Sales by Match (Solution)

let n = 9; // Number of items on ar
let ar = [10,20,20,10,10,30,50,10,20]; // Array of random numbers, (will refer to each number as type)

let pairTypes = []; // Array variable to store pair types
let pairTypesObj = []; // Array variable to store objects by type
let pairs = 0; // Variable to accumulate number of pairs

function sockMerchant(n, ar) {
    for (let i = 0; i < n; i++) { // Iterates over ar
        if (!pairTypes.includes(ar[i])) { // Checks if pairType has been pushed to the pairTypes array
            pairTypes.push(ar[i]); // Pushes to pairTypes array
            pairTypesObj.push({type: ar[i], count:0}); // Creates pair type object with the count property
        }
    }
    for (let i = 0; i < n; i++) { 
        for (let j = 0; j < pairTypesObj.length; j++) { // Iterates over the objects pairTypesObj
          if (ar[i] == pairTypesObj[j].type) { // Check If current Type in the array is equal to the pair types object
            pairTypesObj[j].count++; // If so increment the count property by one
            if (pairTypesObj[j].count == 2) { // Check If the pair type object count property is equal to 2 
              pairs++; // If so then increment pairs by one
            }
          }
          if (pairTypesObj[j].count == 2) {  // Check if pairTypesObj is equal to 2
            pairTypesObj[j].count = 0; // If so then reset it to 0 so it doesn't add aditional pairs
          }
        }
    }
    return pairs;
}

console.log(sockMerchant(n, ar));