AlgoDaily - Merge Sort vs. Quick Sort vs. Heap Sort

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Implementation of Quick Sort

Quick Sort can be implemented using two functions described below:

partition(Array, startIndex, lastIndex)
quick_sort(Array, startIndex, lastIndex)

Here, in the partition function, we are dividing the array based upon the selected pivot. In the quick_sort function, we are re-arranging the elements.

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console.log(quickSort(nums, 0, nums.length - 1))
 
function partition(arr, low, high) {
    let lowIdx = low - 1;
    let pivot = arr[high];  // pivot
​
    for (let j = low; j < high; j++) {
        // If current element is smaller than or
        // equal to pivot
        if (arr[j] <= pivot) {
            // Increment index of left/smaller element
            lowIdx = lowIdx + 1;
            // Swap
            const temp = arr[lowIdx];
            arr[lowIdx] = arr[j];
            arr[j] = temp;
        }
    }
​
    const temp = arr[lowIdx + 1];
    arr[lowIdx + 1] = arr[high];
    arr[high] = temp;
​
    return lowIdx + 1
}
​
function quickSort(arr, low, high) {
    if (arr.length === 1) {
        // Base case
        return arr;
    }

Implementation of Quick Sort

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