quicksort.ts

const items = [4,8,0,3,1,5,7,2,6,9];
console.log(items);
quicksort<number>(items);
console.log(items);

export function quicksort<T>(items: T[]): void {
    quicksortSub(items, 0, items.length-1);
}

function quicksortSub<T>(items: T[], lo: number, hi: number) {
    if(lo < hi) {
        const p = partition<T>(items, lo, hi);
        quicksortSub(items, lo, p-1);
        quicksortSub(items, p+1, hi)
    }
}

function partition<T>(items: T[], lo: number, hi: number): number {
    const pivot = items[hi];
    let i = lo;
    for(let j = lo; j < hi; j++) {
        if(items[j] < pivot) {
            [items[i], items[j]] = [items[j], items[i]];
            i++;
        }
    }
    [items[i], items[hi]] = [items[hi], items[i]];
    return i;
}