题解 | #手机号#C++暴力遍历字符串分类讨论解法

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

int main() {
    int n;
    cin>>n;
    int i=0;
    vector <string> a;
    for(i=0;i<n;i++)
    {
        string b;
        cin>>b;
        a.push_back(b);
    }
    for(i=0;i<n;i++)
    {
        int len=a[i].size();
        if(len==11)
        {
            if((a[i][0]=='1'  &&  a[i][1]=='3'  &&  a[i][2]=='3')  ||  (a[i][0]=='1'  &&  a[i][1]=='5'  &&  a[i][2]=='3')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='0')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='1')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='9'))
            {
                cout<<"China Telecom";
            }
            else 
            {
                if((a[i][0]=='1'  &&  a[i][1]=='3'  &&  a[i][2]=='0')  ||  (a[i][0]=='1'  &&  a[i][1]=='3'  &&  a[i][2]=='1')  ||  (a[i][0]=='1'  &&  a[i][1]=='5'  &&  a[i][2]=='5')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='5')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='6'))
                {
                    cout<<"China Unicom";
                }
                else 
                {
                    if((a[i][0]=='1'  &&  a[i][1]=='3'  &&  a[i][2]=='5')  ||  (a[i][0]=='1'  &&  a[i][1]=='3'  &&  a[i][2]=='6')  ||  (a[i][0]=='1'  &&  a[i][1]=='5'  &&  a[i][2]=='0')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='2')  ||  (a[i][0]=='1'  &&  a[i][1]=='8'  &&  a[i][2]=='8'))
                    {
                        cout<<"China Mobile Communications";
                    }
                    else 
                    {
                        cout<<"-1";
                    }
                }
            }
        }
        else 
        {
            cout<<"-1";
        }
        if(i!=n-1)
        {
            cout<<endl;
        }
    }
    return 0;
}