思路

python做这题很简单，灵活用datetime库即可

code

import os
import sys

# 请在此输入您的代码
import datetime

start = datetime.datetime(1970,1,1,0,0,0)
for _ in range(int(input())):
  ls = input().split()
  end = datetime.datetime.strptime(ls[0]+ls[1],"%Y-%m-%d%H:%M:%S")
  x = int(ls[2])
  n = (end-start)// datetime.timedelta(minutes=x)
  ans = (start + n * datetime.timedelta(minutes = x)).strftime("%Y-%m-%d %H:%M:%S")
  print(ans)