1591C - Minimize Distance - CodeForces Solution

for _ in range(int(input())):
    n,k=map(int,input().split())
    arr=list(map(int,input().split()))
    pos=[]
    neg=[]
    dist=0
    for item in arr:
        if item>=0:
            pos.append(item)
        elif item<0:
            neg.append(item*(-1))
    pos.sort()
    neg.sort()
    if len(neg)==0:
        for i in range(len(pos)-1,-1,-k):
            dist+=2*pos[i]
        dist-=pos[-1] 
    elif len(pos)==0:
        for i in range(len(neg)-1,-1,-k):
            dist+=2*neg[i]
        dist-=neg[-1] 
    elif pos[-1]>neg[-1]:
        for i in range(len(neg)-1,-1,-k):
            dist+=2*neg[i]
        for i in range(len(pos)-1,-1,-k):
            dist+=2*pos[i]
        dist-=pos[-1]
    elif neg[-1]>=pos[-1]:
        for i in range(len(pos)-1,-1,-k):
            dist+=2*pos[i]
        for i in range(len(neg)-1,-1,-k):
            dist+=2*neg[i]
        dist-=neg[-1]
    print(dist)