# Copyright (c) 2015, Bartlomiej Puget <larhard@gmail.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions and the following disclaimer.
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#     this list of conditions and the following disclaimer in the documentation
#     and/or other materials provided with the distribution.
#
#   * Neither the name of the Bartlomiej Puget nor the names of its
#     contributors may be used to endorse or promote products derived from this
#     software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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import math


def euclid_distance(p, q, *args, **kwargs):
    return math.sqrt((p[0]-q[0])**2 + (p[1]-q[1])**2)


def path_length(vertices, distance=euclid_distance):
    result = 0
    for i in range(len(vertices)):
        result += distance(vertices[i], vertices[(i+1) % len(vertices)])
    return result
