题解 | #单词替换#

#include<string>
#include<iostream>
using namespace std;
int main()
{
	string s1,s2,s3;
	string n = " ";
	while (getline(cin, s1))
	{
		getline(cin, s2);
		getline(cin, s3);
		while (s1.find(n + s2 + n) != string::npos || s1.find(s2 + n) == 0 || s1.find(n + s2) == s1.size() - s2.size())
		{
			if (s1.find(n + s2 + n) != string::npos)
			{
				s1.replace(s1.find(n+s2+n), s2.size()+2, n + s3 + n);
			}
			else if (s1.find(s2 + n) == 0)
			{
				s1.replace(s1.find(s2 + n), s2.size() + 1, s3 + n);
			}
			else s1.replace(s1.find(n + s2), s2.size() + 1, n+s3);
		}
		cout << s1 << endl;
	}
	return 0;
	}