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  1. Prepare
  2. Tutorials
  3. 10 Days of Javascript
  4. Day 3: Arrays
  5. Discussions

Day 3: Arrays

  • gaugusto_rfs
     + 0 comments

    Hello! I tried to not use the native sorting function, to really exercise the coding. Since it's a tutorial with the purpose of practicing the language, I've implemented the quicksort:

        let lastIndex = nums.length - 1;
    let sortedNums = quickSort(nums, 0, lastIndex);
    let largest = sortedNums[lastIndex];
    let secondLargest;
    for(let x = lastIndex; x >= 0; x--) {
        if (largest === sortedNums[x])
            continue;
        else {
            secondLargest = sortedNums[x];
            break;
        }         
    }
    return secondLargest;
}
function partition(arr, low, high) {
        let pivot = arr[high];
        let i = low - 1; 
        for(let j = low; j <= high-1; j++){
            if(pivot > arr[j]){              
                i++;                
                swap(arr, i, j);   
            }
        }
        
        swap(arr, i+1, high); 
        return i+1; 
}
function quickSort(arr, low, high) {
        if (high > low) {
            let pi = partition(arr, low, high);
            quickSort(arr, low, pi - 1); 
            quickSort(arr, pi+1, high); 
        } 
        return arr;
}   
function swap(arr, i, j) {
        let temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
}