题解 | #单词替换#

#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main() {
    int a, b,index;
    string s1,s2,s3;
    string res,tmp1,tmp2;
    bool flag;
    vector<string> v;
    while (getline(cin,s1)) { // 注意 while 处理多个 case
        getline(cin,s2);
        getline(cin,s3);
        while(true){
           index=s1.find(' ');
           if(index!=string::npos){
               tmp1=s1.substr(0,index);
               v.push_back(tmp1);
               s1=s1.substr(index+1);
           }
           else break;
        }
        //此时s1已无空格，看看是否为空
        if(s1.size()!=0){
            v.push_back(s1);
        }
        for(int i=0;i<v.size();i++){
            if(v[i]!=s2){
                cout<<v[i];
            }
            else {
                cout<<s3;
            }
            if(i!=v.size()-1)
            cout<<" ";
        }
        cout<<endl;
    }
}
// 64 位输出请用 printf("%lld")