This documentation is automatically generated by online-judge-tools/verification-helper
# verification-helper: PROBLEM https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_A&lang=ja
from pathlib import Path
import sys
sys.path.append(str(Path(__file__).resolve().parent.parent.parent.parent))
def convex_hull(xy, multi=False):
xy.sort(key=lambda x: (x[1], x[0]))
res = []
def cross3(a, b, c):
return (b[0] - a[0]) * (c[1] - a[1]) - (b[1] - a[1]) * (c[0] - a[0])
if multi:
def f(a, b, c):
return cross3(a, b, c) > 0
else:
def f(a, b, c):
return cross3(a, b, c) >= 0
for p in xy:
while len(res) > 1 and f(res[-1], res[-2], p):
res.pop()
res.append(p)
le = len(res)
for p in xy[::-1][1:]:
while len(res) > le and f(res[-1], res[-2], p):
res.pop()
res.append(p)
res.pop()
return res
n = int(input())
xy = [list(map(int, input().split())) for _ in range(n)]
res = convex_hull(xy, True)
print(len(res))
for x, y in res:
print(x, y)Traceback (most recent call last):
File "/opt/hostedtoolcache/Python/3.11.4/x64/lib/python3.11/site-packages/onlinejudge_verify/documentation/build.py", line 81, in _render_source_code_stat
bundled_code = language.bundle(
^^^^^^^^^^^^^^^^
File "/opt/hostedtoolcache/Python/3.11.4/x64/lib/python3.11/site-packages/onlinejudge_verify/languages/python.py", line 108, in bundle
raise NotImplementedError
NotImplementedError