| t | from decimal import Decimal, getcontext | t | from decimal import Decimal, getcontext |
| foo = input() | | foo = input() |
| func = lambda x: eval(foo) | | func = lambda x: eval(foo) |
| d = int(input()) | | d = int(input()) |
| getcontext().prec = d + 2 | | getcontext().prec = d + 2 |
| x = [Decimal(-1.5), Decimal(1.5)] | | x = [Decimal(-1.5), Decimal(1.5)] |
| eps = Decimal(f'1E-{d + 1}') | | eps = Decimal(f'1E-{d + 1}') |
| length = lambda x: x[-1] - x[0] | | length = lambda x: x[-1] - x[0] |
| flag = func(x[0]) < 0 | | flag = func(x[0]) < 0 |
| s = '{:.' + str(d) + 'f}' | | s = '{:.' + str(d) + 'f}' |
| while length(x) > eps: | | while length(x) > eps: |
| t = (x[0] + x[-1]) / 2 | | t = (x[0] + x[-1]) / 2 |
| if func(t) == 0: | | if func(t) == 0: |
| print(s.format(t)) | | print(s.format(t)) |
| break | | break |
| elif func(t) > 0 and flag or (func(t) < 0 and (not flag)): | | elif func(t) > 0 and flag or (func(t) < 0 and (not flag)): |
| x = [x[0], t] | | x = [x[0], t] |
| elif func(t) < 0 and flag or (func(t) > 0 and (not flag)): | | elif func(t) < 0 and flag or (func(t) > 0 and (not flag)): |
| x = [t, x[-1]] | | x = [t, x[-1]] |
| else: | | else: |
| print(s.format(x[1])) | | print(s.format(x[1])) |