题解 | BFS

#include <bits/stdc++.h>
#include <type_traits>
using namespace std;

int main() {
    string a,b="bob";
    cin>>a;
    transform(a.begin(), a.end(), a.begin(), ::tolower);
    if(a.length()<3){
        cout<<-1;
        return 0;
    }
    for (int i=0;i<=a.length()-3;i++){
        if (b==a.substr(i,3)){
            cout<<i;
            return 0;
        }
    }
    cout<<-1;
    return 0;
}
// 64 位输出请用 printf("%lld")