Submission #951348

#	Time	Username	Problem	Language	Result	Execution time	Memory
951348		temmieowo	Colors (BOI20_colors)	C++14	9 / 100	1 ms	596 KiB

Colors

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

const int MAX_N = 5e5+10;
const int INF = 2e18;

int cnt = 0;
int n;
set<int> ss;

int ask(int p){
    if (ss.find(p)!=ss.end()){
        cerr << p << "被用過了\n";
        assert(0);
    }
    ss.insert(p);
    if (cnt==64){
        cout << "問太多次了\n";
        assert(0);
    }
    cnt++;

    cout << "? " << p << endl;

    int res;
    cin >> res;
    return res;
}

void answer(int p){
    cout << "= " << p << endl;
    exit(0);
    return;
}

void solve2(){
    int ll = 1, rr = n;
    while (ll<=rr){
        if (ask(ll)==0 && ll!=1){
            answer(rr-ll+2);
        }
        ll++;

        if (!(ll<=rr)){
            break;
        }

        if (ask(rr)==0){
            answer(rr-ll+2);
        }
        rr--;
    }
    answer(1);
    return;
}

void solve1(){

    // input
    cin >> n;

    // process
    if (n<=64){
        solve2();
    }

    int ll = 1, rr = n+1, ans = rr;
    int now = 1;
    while (ll<rr){
        int mid = (ll+rr)/2;

        int xx = 1;
        int yy = 1;

        ask(xx);
        int res = ask(yy);

        if (res==1){
            ans = mid;
            rr = mid;
        }else{
            ll = mid+1;
        }

        now++;
    }
    answer(ans);

    return;
}

signed main(){

    int t = 1;
    while (t--){
        solve1();
    }

    return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 13
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 33