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82 lines
2.2 KiB
Python
82 lines
2.2 KiB
Python
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#coding: utf-8
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''' mbinary
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#######################################################################
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# File : mapSum.py
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# Author: mbinary
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# Mail: zhuheqin1@gmail.com
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# Blog: https://mbinary.coding.me
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# Github: https://github.com/mbinary
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# Created Time: 2018-12-14 23:11
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# Description:
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实现一个 MapSum 类里的两个方法，insert 和 sum。
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对于方法 insert，你将得到一对（字符串，整数）的键值对。字符串表示键，整数表示值。如果键已经存在，那么原来的键值对将被替代成新的键值对。
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对于方法 sum，你将得到一个表示前缀的字符串，你需要返回所有以该前缀开头的键的值的总和。
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示例 1:
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输入: insert("apple", 3), 输出: Null
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输入: sum("ap"), 输出: 3
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输入: insert("app", 2), 输出: Null
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输入: sum("ap"), 输出: 5
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leetcode-ch:677 https://leetcode-cn.com/problems/map-sum-pairs/
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#######################################################################
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'''
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class node:
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def __init__(self,ch,n=0):
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self.ch = ch
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self.n = n
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self.children={}
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def __getitem__(self,ch):
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return self.children[ch]
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def __setitem__(self,ch,nd):
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self.children[ch]=nd
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def __len__(self):
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return len(self.children)
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def __iter__(self):
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return iter(self.children.values())
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def __delitem(self,ch):
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del self.children[ch]
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def __contains__(self,ch):
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return ch in self.children
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class MapSum:
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def __init__(self):
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"""
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Initialize your data structure here.
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"""
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self.root = node('')
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def insert(self, key, val):
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"""
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:type key: str
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:type val: int
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:rtype: void
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"""
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nd = self.root
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for i in key:
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if i not in nd:
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nd[i] = node(i)
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nd = nd[i]
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nd.n = val
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def visit(self,nd):
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ret = nd.n
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for chd in nd:
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ret+=self.visit(chd)
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return ret
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def sum(self, prefix):
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"""
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:type prefix: str
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:rtype: int
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"""
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nd = self.root
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for ch in prefix:
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if ch in nd:
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nd = nd[ch]
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else:return 0
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return self.visit(nd)
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