Created
April 5, 2021 19:32
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Make a binary tree based on binary numbers
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import sys | |
import itertools | |
def next_power_of_two(v): | |
# From Stanford bit-twiddling hacks: https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2 | |
v -= 1 | |
v |= v >> 1 | |
v |= v >> 2 | |
v |= v >> 4 | |
v |= v >> 8 | |
v |= v >> 16 | |
v |= v >> 32 | |
v += 1 | |
return v | |
def make_tree_for_range(begin, end): | |
assert end >= begin | |
assert isinstance(begin, int) | |
assert isinstance(end, int) | |
assert begin >= 0 | |
print(r'\tikz [binary tree layout, nodes={draw,circle}, font=\sffamily, semithick]') | |
orig_mask = next_power_of_two(begin ^ end) - 1 | |
def print_tree(cur, mask): | |
left = max(cur &~ mask, begin) | |
right = min(cur | mask, end) | |
assert cur|mask >= begin | |
if left == right: | |
print('node{%d} ' % left, end='') | |
else: | |
print('node{%d--%d} ' % (left, right), end='') | |
assert left <= right | |
if cur|(mask>>1) >= begin and mask > 0: | |
print('child { ', end='') | |
print_tree(cur, mask >> 1) | |
print('} ', end='') | |
else: | |
print('child [missing] ', end='') | |
if cur | ((mask + 1) >> 1) <= end and mask > 0: | |
print('child {', end='') | |
print_tree(cur | ((mask + 1) >> 1), mask >> 1) | |
print('} ', end='') | |
else: | |
print('child [missing] ', end='') | |
print('\\', end='') | |
print_tree(begin&~orig_mask, orig_mask) | |
print(';') | |
def main(): | |
make_tree_for_range(int(sys.argv[1]), int(sys.argv[2])) | |
if __name__ == '__main__': | |
main() |
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