实战 - Head of gang - 并查集
- 输入一串序列:Name1 Name2 Time表示A和B的通话时间,假定存在通话的人所在圈子大于2个人,认为是一个黑帮,在这个黑帮中,打电话时间最长的是老大
- 思路:使用并查集的思想构建节点的边关系,同时需要保存每个节点的通话时间
- 注意:①因为在初始化节点、边关系时,所有节点的总通话时间还不确定,所以不能过早确定边关系,等时间确定后,再确定边关系;②我的小弟的小弟还是我的小弟,所以在计算黑帮人数时,不能只计算和boss直接相关的,间接相关的也要计算上。
def headOfGang():
MAX_ = 27
father_ = [i for i in range(MAX_)]
name_ = [None for i in range(MAX_)]
visit_ = [False for i in range(MAX_)]
time_ = [0 for i in range(MAX_)]
height_ = [1 for i in range(MAX_)]
def Initial():
for i in range(MAX_):
father_[i] = i
name_[i] = None
visit_[i] = False
time_[i] = 0
height_[i] = 1
def Find(x):
if x != father_[x]:
father_[x] = Find(father_[x])
return father_[x]
def Union(x, y):
x, y = Find(x), Find(y)
if x != y:
# x的通话时间比y长 -> x是上级
if time_[x] > time_[y]:
father_[y] = x
height_[x] += height_[y] # 把y和他的小弟一起带上
# y的通话时间比x长 -> y是上级
elif time_[x] < time_[y]:
father_[x] = y
height_[y] += height_[x] # 把x和他的小弟一起带上
else:
father_[x] = y
height_[y] += height_[x]
while True:
try:
# n, k分别为电话数和通话时间阈值
n, k = [int(i) for i in input().split()]
x_list, y_list = [], []
for i in range(n):
x, y, time = input().split()
x_index, y_index = ord(x[0]) - ord('A'), ord(y[0]) - ord('A')
time = int(time)
name_[x_index], name_[y_index] = x, y
visit_[x_index], visit_[y_index] = True, True
time_[x_index] += time
time_[y_index] += time
x_list.append(x_index)
y_list.append(y_index)
for x, y in zip(x_list, y_list):
Union(x, y)
gangHead = []
for i in range(MAX_):
if not visit_[i]:
continue
if i == father_[i] and height_[i] > 2 and time_[i] > k:
gangHead.append(i)
gangHead.sort()
if len(gangHead):
print(len(gangHead))
for i in gangHead:
print('{} {}'.format(name_[i], height_[i]))
else:
print(0)
Initial()
except (EOFError, KeyboardInterrupt):
break
if __name__ == '__main__':
headOfGang()