677. Map Sum Pairs-白红宇

677. Map Sum Pairs

阅读量：5065 次

发布时间：2019-06-12

本文共 2598 字，大约阅读时间需要 8 分钟。

Implement a MapSum class with insert, and sum methods.

For the method insert, you'll be given a pair of (string, integer). The string represents the key and the integer represents the value. If the key already existed, then the original key-value pair will be overridden to the new one.

For the method sum, you'll be given a string representing the prefix, and you need to return the sum of all the pairs' value whose key starts with the prefix.

Example 1:

Input: insert("apple", 3), Output: NullInput: sum("ap"), Output: 3Input: insert("app", 2), Output: NullInput: sum("ap"), Output: 5

class MapSum {    map
     
       mp;public:    /** Initialize your data structure here. */    MapSum() {}        void insert(string key, int val) {        mp[key]=val;    }        int sum(string prefix) {        /*        if (mp.find(prefix)==mp.end()){            return 0;        }        */        int res=0, n=prefix.size();                for(auto iter=mp.lower_bound(prefix);iter!=mp.end();++iter)        {            if(iter->first.substr(0,n)!=prefix)                break;            res+=iter->second;        }        return res;    }};/** * Your MapSum object will be instantiated and called as such: * MapSum obj = new MapSum(); * obj.insert(key,val); * int param_2 = obj.sum(prefix); */

c++ map lower_bound upper_bound用法

运行 https://www.cnblogs.com/billin/archive/2011/09/01/2162102.html 一下代码就知道了

#include#include
      
       int main(){    using namespace std;    map
       
         m1;    map
        
         ::const_iterator m1_AcIter,m1_RcIter;    typedef pair
         
           Int_Pair;    m1.insert(Int_Pair(1,10));    m1.insert(Int_Pair(2,20));    m1.insert(Int_Pair(3,30));    m1_RcIter=m1.lower_bound(2);    cout<<"The first elem of map m1 with a key greater than 2 is: "    <
          
           second<<"."<
           
            second<<"."<
            
             first); cout<<"The element of m1 with a key mathing the last element is: " <
             
              second<<"."<

输出

python代码

class MapSum(object):    def __init__(self):        """        Initialize your data structure here.        """        self.d={}            def insert(self, key, val):        """        :type key: str        :type val: int        :rtype: void        """        self.d[key]=val            def sum(self, prefix):        """        :type prefix: str        :rtype: int        """        return sum(self.d[i] for i in self.d if i.startswith(prefix))         # Your MapSum object will be instantiated and called as such:# obj = MapSum()# obj.insert(key,val)# param_2 = obj.sum(prefix)

转载于:https://www.cnblogs.com/learning-c/p/9271525.html

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