求一个字符串中出现次数最多的字母

#  输入一段字符串,英文字母,求出现次数最多的字母
def getMaxChar(s):
    mp = {}
    maxCount = 0
    maxs =[]
    for i in s:
        mp[i] = mp.get(i,0)+1
        if mp[i]>maxCount:
            maxCount = mp[i]
    for k in mp:
        if mp[k] == maxCount:
            maxs.append(k)
    return maxs

getMaxChar('adfoweyirlkblasgxalueralsdhg')

时间复杂度分析，基本操作为 遍历字符串，hash get put 操作，还有遍历hash ,不难得出时间复杂度为 O(n),空间复杂度 为O(1)