Submission #1288403

#	Time	Username	Problem	Language	Result	Execution time	Memory
1288403		edo	Colors (BOI20_colors)	C++20	100 / 100	2 ms	424 KiB

Colors

#include <bits/stdc++.h>

using namespace std;
using ll   = long long;
using vi   = vector<int>;
using vll  = vector<ll>;
using vvi  = vector<vi>;
using vvll = vector<vll>;
using pii  = pair<int,int>;
using pll  = pair<ll,ll>;
using ui    = unsigned int;
using ull   = unsigned long long;
using pui   = pair<ui,ui>;
using pull  = pair<ull,ull>;

template<typename T>
using vc = std::vector<T>;


#define YES cout << "YES\n"
#define NO  cout << "NO\n"
#define yes cout << "yes\n"
#define no  cout << "no\n"
#define Yes cout << "Yes\n"
#define No  cout << "No\n"

template<typename T> void sc(T &x) { cin >> x; }
template<typename T, typename U> void sc(pair<T,U> &p) { sc(p.first), sc(p.second); }
template<typename T> void sc(vector<T> &v) { for (auto &x : v) sc(x); }
template<typename... A> void sc(A&... a) { (sc(a), ...); }


template<typename T> void _pt(const T &x){cout << x;}
template<typename T, typename U> void _pt(const pair<T,U> &p){_pt(p.first); cout << ' '; _pt(p.second);}
template<typename T> void _pt(const vector<T> &v){bool f=1; for(auto &x:v){if(!f) cout<<' '; _pt(x); f=0;}}
template<typename... A> void pt(const A&... a){(_pt(a), ...);}


template<typename T, typename U> bool umin(T &a, const U &b) { return b < a ? (a = b, true) : false; }
template<typename T, typename U> bool umax(T &a, const U &b) { return b > a ? (a = b, true) : false; }

#define GET_MACRO(_1,_2,_3,_4,NAME,...) NAME
#define FOR1(n)            for (int i=0; i<(n); ++i)
#define FOR2(i,n)          for (int i=0; i<(n); ++i)
#define FOR3(i,l,r)        for (int i=(l); i<(r); ++i)
#define FOR4(i,l,r,k)      for (int i=(l); i<(r); i+=(k))
#define FOR(...)           GET_MACRO(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define ROF1(n)            for (int i=(n)-1; i>=0; --i)
#define ROF2(i,n)          for (int i=(n)-1; i>=0; --i)
#define ROF3(i,l,r)        for (int i=(r)-1; i>=(l); --i)
#define ROF4(i,l,r,k)      for (int i=(r)-1; i>=(l); i-=(k))
#define ROF(...)           GET_MACRO(__VA_ARGS__, ROF4, ROF3, ROF2, ROF1)(__VA_ARGS__)
#define all(c)   (c).begin(), (c).end()
#define allr(c)  (c).rbegin(), (c).rend()
#define eb       emplace_back
#define mp       make_pair
#define mt       make_tuple
#define fi       first
#define se       second
#define pb       push_back
#define trav(x,a) for (auto &x : (a))
#define sz(a) ((int)(a).size())
#define mem(a,v) memset(a, v, sizeof(a))
#define nl pt("\n")

ll n;

void solve() {
    ll l = 1, r = n - 1;
    ll p = n, t = 0, d = 0;

    auto ask = [&](ll x) {
        pt("? ", x); nl; cout << flush;
        sc(x);
        return x;
    };

    while(l <= r) {
        ll m = (l + r) >> 1;
        d += t ? -m : m;
        umin(p, n - d);
        t ^= 1;
        l = m + 1;
    }
    l = 1; t = 0;
    ll ans = n;
    ask(p);
    while(l <= r) {
        ll m = (l + r) >> 1;
        ll np = p + (t ? -m : m); 
        if(ask(np)) ans = m, r = m - 1;
        else l = m + 1;
        t ^= 1; p = np;
    }
    pt("= ", ans); nl; cout << flush;
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    sc(n);
    solve();
    return 0;
}

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