# Source code for tryalgo.interval_cover

```#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""\
Minimum interval cover

jill-jênn vie et christoph dürr - 2014-2020
"""

from sys import stdin
from math import sqrt

# pylint: disable=redefined-outer-name

def _solve(iles, rayon):
II = []
for x, y in iles:
if y > rayon:
return -1               # island is too far
z = sqrt(rayon * rayon - y * y)   # find the interval
II.append((x + z, x - z))
II.sort()                        # sort by right side
sol = 0
last = float('-inf')
for right, left in II:
if last < left:             # uncovered interval
sol += 1
last = right            # put an antenna
return sol

# snip{

[docs]
def interval_cover(I):
"""Minimum interval cover

:param I: list of closed intervals
:returns: minimum list of points covering all intervals
:complexity: O(n log n)
"""
S = []
# sort by right endpoints
for start, end in sorted(I, key=lambda v: v[1]):
if not S or S[-1] < start:
S.append(end)
return S

# snip}

if __name__ == "__main__":
# http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1360
testCase = 1
while True: