Submission #284541

#	Time	Username	Problem	Language	Result	Execution time	Memory
284541		AaronNaidu	Strange Device (APIO19_strange_device)	C++14	100 / 100	3895 ms	76844 KiB

strange_device

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;

ll n, a, b, l, r, per;
set<pair<ll, ll> > segments, newSegments;

ll gcd(ll x, ll y) {
    //cout << "GCD of " << x << " " << y << "\n";
    if (y == 0)
    {
        return x;
    }
    return gcd(y, x % y);
}

void addSegment(ll sta, ll fin) {
    //newSegments = segments;
    auto startPos = segments.upper_bound({sta, per});
    vector<pair<ll, ll>> toErase;
    if (startPos == segments.begin())
    {
        for (auto i = segments.begin(); i != segments.end(); i++)
        {
            if (i->first <= fin)
            {
                fin = max(fin, i->second);
                toErase.push_back({i->first, i->second});
            }
            else
            {
                break;
            }
        }
        for (int i = 0; i < toErase.size(); i++)
        {
            segments.erase({toErase[i].first, toErase[i].second});
        }
        segments.insert({sta, fin});
        return;
    }
    startPos--;
    if (startPos->second >= sta)
    {
        sta = min(sta, startPos->first);
        fin = max(fin, startPos->second);
        toErase.push_back({startPos->first, startPos->second});
    }
    startPos++;  
    for (auto i = startPos; i != segments.end(); i++)
    {
        if (i->first <= fin)
        {
            fin = max(fin, i->second);
            toErase.push_back({i->first, i->second});
        }
        else
        {
            break;
        }
    }
    for (int i = 0; i < toErase.size(); i++)
    {
        segments.erase({toErase[i].first, toErase[i].second});
    }
    segments.insert({sta, fin});     
}

int main() {
    cin >> n >> a >> b;
    //segments.insert({0, 1});
    //segments.insert({1000000000000000000, 0});
    per = gcd(a, b+1);
    ld A = a;
    ld B = b;
    ld t = A/(1000000000000000007) * B;
    if (t > per)
    {
        per = 1000000000000000007;
    }
    else
    {
        per = round(A/per * B);
    }
    cin >> l >> r;
    if (r-l+1 >= per)
    {
        cout << per << "\n";
        return 0;
    }
    l = l%per;
    r = r%per;
    if(l <= r) {
        segments.insert({l, r});
        //segments.push_back({r, 1});
    }
    else
    {
        segments.insert({0, r});
        //segments.push_back({r, 1});
        segments.insert({l, per-1});
        //segments.push_back({per-1, 1});
    }
    for (int i = 1; i < n; i++)
    {
        cin >> l >> r;
        if (r-l+1 >= per)
        {
        cout << per << "\n";
        return 0;
        }
        l = l%per;
        r = r%per;
        if (l <= r)
        {
            addSegment(l, r);
        }
        else
        {
            addSegment(0, r);
            addSegment(l, per-1);
        }
    }
    ll runningTotal = 0;
    for (auto i : segments)
    {
        runningTotal += i.second - i.first + 1;
    }
    cout << runningTotal << "\n";
}

Compilation message (stderr)

strange_device.cpp: In function 'void addSegment(ll, ll)':
strange_device.cpp:36:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         for (int i = 0; i < toErase.size(); i++)
      |                         ~~^~~~~~~~~~~~~~~~
strange_device.cpp:63:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |     for (int i = 0; i < toErase.size(); i++)
      |                     ~~^~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20
• Subtask 8: 30 / 30