Google Code Jam -- Blindfolded Bullseye -- Solution in Python

codejam_2020_r1b_b.py

# usage:  (python3 a.py < a.in) > a.out
import time, sys, inspect, platform

print = lambda *a, **k: __builtins__.print(str(inspect.currentframe().f_back.f_lineno)+':',
    *a, file=sys.stderr, **k) if platform.node() in ['surfux', 'ssd'] else ...

class EndTestCase(Exception): pass

#---------------------------------------------

t, a, b = [int(x) for x in input().split()]

def guess(x, y):
    __builtins__.print(str(x) + ' ' + str(y))
    answer = input()
    print(answer, 'for input', x, y)
    if answer == 'CENTER':
        raise EndTestCase
    return answer == 'HIT'


# Search on the interval [lo,hi)                                vvvv
# Return first index where test_func is True  -> [False..False, True..True]
# This will fail when the list is all False
def bin_search(lo, hi, test_func):
    print('Calling bin_search with ', lo, hi)
    if lo == hi - 1:
        return lo
    mid = (hi+lo-1)//2
    if test_func(mid):
        return bin_search(lo, mid + 1, test_func)
    else:
        return bin_search(mid + 1, hi, test_func)


def get_startpos():
    for x,y in [(-10**9//2,0), (0,-10**9//2), (0,0), (0,10**9//2), (10**9//2,0)]:
        if guess(x,y):
            return (x,y)

def case():
    startpos = get_startpos()
    print(startpos)

    x_lo = bin_search(-10**9, startpos[0]+1, lambda x:     guess(x, startpos[1]) )
    x_hi = bin_search(startpos[0], 10**9+2,  lambda x: not guess(x, startpos[1]) ) - 1
    y_lo = bin_search(-10**9, startpos[1]+1, lambda y:     guess(startpos[0], y) )
    y_hi = bin_search(startpos[1], 10**9+2,  lambda y: not guess(startpos[0], y) ) - 1

    print('************', x_lo, x_hi, y_lo, y_hi)

    x_avg = (x_lo + x_hi) // 2
    y_avg = (y_lo + y_hi) // 2

    guess(x_avg, y_avg)
    raise Exception('this line should never be reached')


for _ in range(t):
    try:
        case()
    except EndTestCase:
        pass