📑 Saving The Universe Again

Codejam Qualification Round 2018. Task 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))