Python 反转字符串

#
# 寻找最后的山峰
# @param a int整型一维数组 
# @return int整型
#
class Solution:
    def solve(self , a ):
        # write code here
        if len(a)==1:
            return 0
        na=a[::-1]
        for i in range(0,len(na)):
            if na[-1]<na[i] and na[i]>na[i+1]:
                return len(a)-i-1