Compound Words
You are to find all the two-word compound words in a dictionary. A two-word compound word is a word in the dictionary that is the concatenation of exactly two other words in the dictionary.
Input
Standard input consists of a number of lowercase words, one per line, in alphabetical order. There will be no more than 120,000 words.
Output
Your output should contain all the compound words, one per line, in alphabetical order.
Sample Input
a
alien
born
less
lien
never
nevertheless
new
newborn
the
zebra
Sample Output
alien
newborn
题目大意:求出一个由两个单词组成的单词,并按照字典序输出。
解析:这题比较简单,直接暴力用map暴力求解,详见代码。
ps:(本来老师是让我们用哈希做的,但是我想用一下map,索性就用map暴力了一下,当然set也可以)
#include<map>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
map<string,int> mp;
map<string,int> ::iterator it;//mp的迭代器
string s;
int main()
{
while(cin>>s) { mp[s]=1; }//输入每个单词;
for(it=mp.begin();it!=mp.end();it++)//从第一个单词开始搜,
{
//重新重组单词,看看重组单词在输入过的单词里有没有存在
//以案例里的alien为例,重组单词,总有一种重组情况为a和lien。此时在这两个单词是存在的,输出
for(int i=1;i< it->first.size()-1;i++)//重组单词,it->first.size()指在迭代器下的string的长度,
{
string s1,s2;
s1=it->first.substr(0,i);//重组第一个单词 ,substr为字符串复制,复制it->first()对应的字符串的第0个到第i个
s2=it->first.substr(i,it->first.size()-1);//重组第二个单词
if(mp.find(s1)!=mp.end()&&mp.find(s2)!=mp.end())//如果这两个单词是存在的,输出
{
cout<<it->first<<endl;
break;
}
}
}
return 0;
}