1.4 KB | 1478 chars
"""
[25318: solved.ac 2022](https://www.acmicpc.net/problem/25318)
Tier: Silver 1
Category: implementation, string
"""
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
SYS_INPUT = True
RECURSION_LIMIT = 10 ** 7
SET_RECURSION = False
BLANK = " "
if SET_RECURSION:
sys.setrecursionlimit(RECURSION_LIMIT)
inp = lambda : sys.stdin.readline().rstrip() if SYS_INPUT else input()
mii = lambda : [*map(int,inp().split())]
mfi = lambda : [*map(float,inp().split())]
ii = lambda : int(inp())
fi = lambda : float(inp())
isplit = lambda : inp().split()
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
n = ii()
if n == 0:
return 0
l = [inp().split() for _ in range(n)]
tms = []
for a, b, tier in l:
tier = int(tier)
Y, M, D = map(int, a.split("/"))
h, m, s = map(int, b.split(":"))
tm = datetime(Y, M, D, h, m, s)
tms.append([tm, tier])
tms.sort(key = lambda t:t[0])
weight = []
last_t = tms[-1][0]
for i in range(n):
tm, tier = tms[i]
weight.append(max((0.5) ** ((last_t - tm).days / 365), 0.9 ** (n - (i + 1))))
down = sum(weight)
up = 0
for i in range(n):
up += tms[i][1] * weight[i]
# p(up, down, up / down)
# p(weight)
return up / down
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()
p(ret)