删除重复字符串
解法：python 函数灵活运用O(n)
import sys
s=sys.stdin.readline().strip() #s="banana"
result=""
for item in s:
if item not in result:
result = result + item
print(result)类似题目：删除重复单词
import sys
s=sys.stdin.readline().strip().split() #
print(s)
result=[]
#[result.append(item) for item in s if item not in result] #利用列表独特方法，更简洁
for item in s:
if item not in result:
result.append(item)
print(result)
print(" ".join(result))