pwnable.kr 上的 coin1

這題需要在時間限制內贏100次二分猜數遊戲。
記得數據結構課上老師就說過，二分查找的實現還是很容易錯的。一開始寫的版本總是用光次數猜不對。
網速比較慢的話就得先用其他題的賬戶登上去然後本地連接到9007端口執行。

from pwn import *

sh = remote('pwnable.kr', 9007)
sh.recvuntil('starting in 3 sec')
print 'Waiting for 3 sec to start ...'

def play_round():
    sh.recvuntil('N=')
    N = int(sh.recvuntil(' '))
    print 'N=%d' % N
    sh.recvuntil('C=')
    C = int(sh.recvuntil('\n').replace('\n', '').rstrip())
    print 'C=%d' % C

	# binary search
    lo = 0
    hi = N-1
    cnt = 0
    re = -1
    while lo < hi:
        cnt += 1
        mi = lo + (hi - lo) / 2
        guess = ' '.join([str(i) for i in range(lo, mi+1)])
        # print 'Test #', cnt, 'range: [%4d, %4d]' % (lo, hi), 'Guess: [%4d, %4d]', lo, mi
        sh.sendline(guess)
        re = int(sh.recvline())
        # print 'Ret:', re
        if re < 10 * (mi - lo + 1):
            hi = mi
        else:
            lo = mi+1
    while  cnt < C:
        cnt += 1
        sh.sendline(str(lo))
        re = int(sh.recvline())
    print 'Aha! Found:', lo, 'Sending...'
    sh.sendline(str(lo))
    print sh.recvuntil('\n') # receive "Congraduate (#round_number)"

win = 0
while win < 100:
    play_round()
    win += 1

sh.interactive()