#?-*-?coding:?utf-8?-*-
“““
Edmonds-Karp?algorithm?for?maximum?flow?problems.
“““

__author__?=?“““ysitu?“““
#?Copyright?（C）?2014?ysitu?
#?All?rights?reserved.
#?BSD?license.

import?networkx?as?nx
from?networkx.algorithms.flow.utils?import?*

__all__?=?[‘edmonds_karp‘]


def?edmonds_karp_core（R?s?t?cutoff）:
????“““Implementation?of?the?Edmonds-Karp?algorithm.
????“““
????R_node?=?R.node
????R_pred?=?R.pred
????R_succ?=?R.succ

????inf?=?R.graph[‘inf‘]
????def?augment（path）:
????????“““Augment?flow?along?a?path?from?s?to?t.
????????“““
????????#?Determine?the?path?residual?capacity.
????????flow?=?inf
????????it?=?iter（path）
????????u?=?next（it）
????????for?v?in?it:
????????????attr?=?R_succ[u][v]
????????????flow?=?min（flo