add ex 747 in python
add ex 747 in python

Mlieou/oj_solutions,Mlieou/lXXtcode,Mlieou/lXXtcode,Mlieou/oj_solutions,Mlieou/leetcode_python,Mlieou/oj_solutions,Mlieou/oj_solutions,Mlieou/lXXtcode,Mlieou/lXXtcode