Submission #951490

#	Time	Username	Problem	Language	Result	Execution time	Memory
951490		phoenix0423	Colors (BOI20_colors)	C++17	100 / 100	3 ms	768 KiB

Colors

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
int t, pre;

bool qry(int x){
    cout<<"? "<<x<<endl;
    cin>>x;
    return x;
}
signed main(void){
    int n;
    cin>>n;
    vector<int> step;
    int l = 0, r = n;
    while(l + 1 < r){
        int m = (l + r) / 2;
        step.pb(m);
        l = m;
    }
    reverse(step.begin(), step.end());
    int pos = 1;
    for(int i = 0; i < step.size(); i++){
        pos += step[i] * (i % 2 ? -1 : 1);
    }
    qry(pos);
    l = 0, r = n;
    int sign = (step.size() % 2 ? -1 : 1);
    while(l + 1 < r){
        int m = (l + r) / 2;
        if(qry(pos + sign * m)) r = m;
        else l = m;
        pos += sign * m;
        sign *= -1;
    }
    cout<<"= "<<r<<endl;
}

Compilation message (stderr)

Colors.cpp: In function 'int main()':
Colors.cpp:30:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int i = 0; i < step.size(); i++){
      |                    ~~^~~~~~~~~~~~~

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