PAT1071. Speech Patterns (25)

题目要求的Word定义 Here a "word" is defined as a continuous sequence of alphanumerical characters separated by non-alphanumerical characters or the line beginning/end.  所以 can""can""can 中应该是3个单词

#include <iostream>
#include <cctype>
#include <map>
using namespace std;
map<string,int> m;
void trims(string &s){
	int isFront=1,isBack=1;
	for(int i=0;i<s.size();i++) {
			
			if(isFront){
				if(!isalnum(s[i])) {
					s.erase(s.begin()+i);
					i--;
				}
				else isFront=0;
			}
	}
	for(int i=s.size()-1;i>=0;i--){
			if(isBack){
				if(!isalnum(s[i])){
					s.erase(s.begin()+i);
				}
				else isBack=0;
			}
	}
}

int main()
{
	string s;
	int c=0;
	while(cin>>s){
		for(int i=0;i<s.size();i++) {
			s[i]=tolower(s[i]);
		}
		c++;
		trims(s);
		int i;string s1;
		while(!s.empty()){
			int len=s.size();
			for(i=0;i<s.size();i++){
				if(!isalnum(s[i])) break;
			}
			if(i!=len) {
				s1=s.substr(0,i);
				trims(s1);
				s=s.substr(i);
				trims(s);
			}else{
				s1=s;
			}
			if(!s1.empty())
				m[s1]++;
			if(i==len) break;
		}
	}
	map<string,int>::iterator ii=m.begin();
	int max=-1;
	string key;
	while(ii!=m.end()){
		if(ii->second>max){
			max=ii->second;
			key=ii->first;
		}else if(ii->second==max){
			if(key>ii->first){
				key=ii->first;
			}
		}
		ii++;
	}
	cout<<key<<" "<<max<<endl;


	return 0;
}