Submission #407379

#	Time	Username	Problem	Language	Result	Execution time	Memory
407379		Victor	Triangles (CEOI18_tri)	C++17	0 / 100	1 ms	320 KiB

tri

#include <bits/stdc++.h>

#include "trilib.h"

using namespace std;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define per(i, a, b) for (int i = b - 1; i >= (a); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back

#define umap unordered_map
#define uset unordered_set

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;

const int INF = 1000000007;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    bitset<40001> taken;
    int n = get_n();
    vi cities;

    rep(i, 2, n + 1) {
        int lo = 0, hi = sz(cities);
        while (lo != hi) {
            int mid = (lo + hi) >> 1;
            if (is_clockwise(1, cities[mid], i))
                hi = mid;
            else
                lo = mid + 1;
        }
        cities.insert(cities.begin() + lo, i);
    }

    stack<int> s;
    s.push(1);
    s.push(cities[0]);
    cities.pb(1);

    rep(i, 1, sz(cities)) {
        int b = s.top(), c = cities[i];
        s.pop();
        int a = s.top();

        if (!is_clockwise(a, b, c)) s.push(b);
        s.push(c);
    }

    s.pop();

    vi hull;
    while (!s.empty()) {
        hull.pb(s.top());
        s.pop();
    }

    hull.pop_back();

    if (is_clockwise(hull.back(), 1, hull[0])) hull.pb(1);

    /*
    reverse(all(hull));
    trav(city, hull) cout << city << ' ';
    cout << endl;*/

    give_answer(sz(hull));
    return 0;
}

Compilation message (stderr)

tri.cpp: In function 'int main()':
tri.cpp:7:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 | #define rep(i, a, b) for (int i = a; i < (b); ++i)
      |                                        ^
tri.cpp:52:5: note: in expansion of macro 'rep'
   52 |     rep(i, 1, sz(cities)) {
      |     ^~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 25