話不多說，debug一遍就可以完全看懂

#!/usr/bin/python
# coding=utf-8
# dag 分詞


word_dict = {
    u'我是': 30,
    u'是小帥': 60,
    u"我": 1,
    u"是": 1,
    u"小帥哥": 18,
    u"哥": 1
}


#
def get_dag(txt):
    dag_dict = {}
    n = len(txt)
    for idx in range(n):
        tmp_list = [idx]
        frag = txt[idx:idx + 2]
        i = idx + 1
        while i < n:
            if frag in word_dict:
                tmp_list.append(i)

            i += 1
            frag = txt[idx:i + 1]
        if len(tmp_list) > 0:
            dag_dict[idx] = tmp_list
    return dag_dict


def get_route(dag_dict, txt):
    n = len(txt)
    route_dict = {n: [0, 0]}
    for idx in range(n - 1, -1, -1):
        max_weight = 0
        if idx not in dag_dict:
            route_dict[idx] = [1, idx]
            continue
        for x in dag_dict[idx]:
            frag = txt[idx:x + 1]
            cur_weight = word_dict[frag] if frag in word_dict else 0
            total_weight = cur_weight + route_dict[x + 1][0]
            if total_weight > max_weight:
                max_weight = total_weight
                route_dict[idx] = [total_weight, x]
    return route_dict


def get_words(route_dict, txt):
    n = len(txt)
    word_list = []
    idx = 0
    while idx < n:
        edx = route_dict[idx][1]
        word = txt[idx:edx + 1]
        word_list.append(word)
        idx = edx + 1
    return word_list


query = u'我是小帥哥'
dag = get_dag(query)
route = get_route(dag, query)
words = get_words(route, query)
print('-'.join(words))