📑 Qualification Round 2018

Task 1. Saving The Universe Again

📓 Variant 1. Python Only

def damage(SC):
    K,D,N=1,0,len(SC)
    if 'C' not in SC:
        D==N
    for i in range(N):
        if SC[i]=='S':
            D+=K
        else:
            K*=2
    return D
def reduce_damage(SC,D):
    C,N=0,len(SC)      
    if damage(SC)>D:
        while 'CS' in SC:
            idx=SC[::-1].index('SC')
            SC=SC[:N-idx-2]+'SC'+SC[N-idx:]
            C+=1
            if damage(SC)<=D:
                break
    return C,damage(SC)-D
T=int(input())
for t in range(T): 
    [D,SC]=input().split()
    D=int(D)
#    print(D,damage(SC))
#    print(reduce_damage(SC,D))
    C,DIFF=reduce_damage(SC,D)
    if DIFF>0:
        print('Case #{}: IMPOSSIBLE'.format(t+1))
    else:
        print('Case #{}: {}'.format(t+1,C))

📓 Variant 1. SageMath Interactive

Task 2. Trouble Sort

📓 Variant 1. Python Only

def trouble_sort(L,N):
    LE,LO=[],[]
    for i in range(N):
        (LO,LE)[i%2==0].append(L[i])
    LE=sorted(LE)
    LO=sorted(LO)
    L=sorted(L)
    for i in range(N):
        if i%2==0:
            el=LE[i//2]
        else:
            el=LO[i//2]
        if el!=L[i]:
            break
    if N-1!=i:
        return str(i)
    else: 
        return 'OK'
T=int(input())
for t in range(T):
    N=int(input())
    L=list(map(int,input().split()))
    ANS=trouble_sort(L,N)
    print('Case #{}: {}'.format(t+1,ANS))

📓 Variant 1. SageMath Interactive

Task 3. Go, Gopher!

📓 Process Simulation

📓 Variant 1. Python Only

#10pts, RE for the last ✓
def go_gopher(a):
    k=a//3+1
    l=k//3
    ra=[3*i+2 for i in list(range(l))]
    if k-1>ra[-1]:
        ra+=[k-1]
    c=1000
    go_ra=[ra[j%len(ra)] for j in range(c)]
    for i in go_ra:
        out_xy='%d 2'%i
        print(out_xy,flush=True)
        in_xy=input()
        if in_xy=='0 0':
            break
        elif in_xy=='-1 -1':
            exit()
T=int(input())
for i in range(T):
    A=int(input())
    go_gopher(A)

📓 Variant 2. Python Only

#10pts, 20pts   ✓ ✓
def go_gopher(a):
    k=a//3+1
    l=k//3
    ra=[3*i+2 for i in list(range(l))]
    if k-1>ra[-1]:
        ra+=[k-1]
    c=1000
    go_ra=[ra[j%len(ra)] for j in range(c)]
    for i in go_ra:
        x,y=[i-1,i,i+1],[1,2,3]
        xy=[' '.join([str(el) for el in [xy1,xy2]]) 
            for xy1 in x for xy2 in y]
        flag=False
        while xy!=[]:
            out_xy='%d 2'%i
            print(out_xy,flush=True)
            in_xy=input()
            if in_xy in xy:
                xy.remove(in_xy)
            elif in_xy=='0 0':
                flag=True
                break
            elif in_xy=='-1 -1':
                exit()                
#            print(xy)
        if flag==True:
            break
T=int(input())
for i in range(T):
    A=int(input())
    go_gopher(A)

📓 Variant 2. SageMath Interactive

Task 4. Cubic UFO

📓 Variant 1. Python Only

📓 Variant 1. SageMath Interactive