剑指 Offer 50. 第一个只出现一次的字符

剑指 Offer 50. 第一个只出现一次的字符 - 力扣（LeetCode）https://leetcode.cn/problems/di-yi-ge-zhi-chu-xian-yi-ci-de-zi-fu-lcof/暴力的三种写法，

字典中可以把键值对一起取出来

思路都是遍历

class Solution:
    def firstUniqChar(self, s):
        dic={}
        if s==' ':
            return ' '
        for i in s:
            dic[i]=0
        for i in s:
            dic[i]+=1
        for i in s:
            if dic[i]==1:
                return i
        return ' '

a=Solution()
s = "abaccdeff"
print(a.firstUniqChar(s))
s1=" "
print(a.firstUniqChar(s1))

'''
dic={'a':0,'b':1,2:'d'}
for i in dic:
    print(i)#a,b,2
print('a' in dic)#返回True
s=""
for i in s:
    print(i,'***')
'''
class Solution:
    def firstUniqChar(self, s):
        dic={}
        for i in s:#s为空字符串不会执行这个for语句
            dic[i]=  not i in dic#出现次数大于等于2就赋值0
        for i in s:
            if dic[i]:
                return i
        return ' '

a = Solution()
s = "abaccdeff"
print(a.firstUniqChar(s))
s1 = " "
print(a.firstUniqChar(s1))

'''
#items()-->获取字典中所有key-value对
scores={'张三':100,'李四':98,'王五':45}
item=scores.items()
print(item,type(item))
for i in item:
    print(i)
for i,j in item:
    print(i,j)
'''
class Solution:
    def firstUniqChar(self, s):
        dic={}
        for i in s:#s为空字符串不会执行这个for语句
            dic[i]=  not i in dic#出现次数大于等于2就赋值0
        for i,j in dic.items():
            if j:
                return i
        return ' '

a = Solution()
s = "abaccdeff"
print(a.firstUniqChar(s))
s1 = " "
print(a.firstUniqChar(s1))