Python 数据结构与算法分析 七、图算法之广度优先搜索

词梯图的构建

from pythonds.graphs import Graph
def buildGraph(wordFile):
    d = {}
    g = Graph()

    wfile = open(wordFile, 'r')
    # 创建词桶
    for line in wfile:
        word = line[:-1]
        for i in range(len(word)):
            bucket = word[:i] + '_' + word[i+1:]
            if bucket in d:
                d[bucket].append(word)
            else:
                d[bucket] = [word]
    # 为同一个通风中的单词添加顶点和边
    for bucket in d.keys():
        for word1 in d[bucket]:
            for word2 in d[bucket]:
                if word1 != word2:
                    g.addEdge(word1, word2)
    return g

广度优先搜索的实现