p1

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

enum State { S0, S1, S2, S3 };

bool acceptsString(const string& input) {
    State currentState = S0;
    for (char c : input) {
        switch (currentState) {
            case S0:
                if (c == '1') currentState = S1;
                break;
            case S1:
                if (c == '1') currentState = S2;
                else currentState = S0;
                break;
            case S2:
                if (c == '1') currentState = S3;
                else currentState = S0;
                break;
            case S3:
                break; // stay in S3
        }
    }
    return currentState == S3;
}

int main() {
    string input;
    cout << "Enter a binary string: ";
    cin >> input;
    if (acceptsString(input)) {
        cout << "Accepted (contains 111)" << endl;
    } else {
        cout << "Rejected (does not contain 111)" << endl;
    }
    return 0;
}