【題解】Google Code Jam 2020 Qualification Round – ESAb ATAd

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

int t, b, a[105], s, d, l, r, cnt, tmp;
char c;

int main(){
    cin >> t >> b;
    while (t--){
        memset(a, -1, sizeof(a));
        s = -1;
        d = -1;
        l = 1;
        r = b;
        cnt = 0;
        while (l <= r){
            if (cnt%10 == 0){
                if (s != -1){
                    cout << s << endl;
                    cnt++;
                    cin >> tmp;
                    if (tmp != a[s]){
                        for (int j = 1; j <= l; j++){
                            a[j] ^= 1;
                        }
                        for (int j = r; j <= b; j++){
                            a[j] ^= 1;
                        }
                    }
                }
                if (d != -1){
                    cout << d << endl;
                    cnt++;
                    cin >> tmp;
                    if (tmp != a[d]){
                        for (int j = 1; j <= l; j++){
                            swap(a[j], a[b+1-j]);
                        }
                    }
                }
            }
            if (cnt%10 == 9){
                cout << 1 << endl;
                cnt++;
                cin >> tmp;
                continue;
            }
            cout << l << endl;
            cnt++;
            cin >> a[l];
            cout << r << endl;
            cnt++;
            cin >> a[r];
            if (a[l] == a[r] && s == -1) s = l;
            if (a[l] != a[r] && d == -1) d = l;
            l++;
            r--;
        }
        for (int i = 1; i <= b; i++){
            cout << a[i];
        }
        cout << endl;
        cin >> c;
        if (c == 'N') return 0;
    }
}