Submission #721549

#	Time	Username	Problem	Language	Result	Execution time	Memory
721549		joelgun14	Strange Device (APIO19_strange_device)	C++17	10 / 100	864 ms	66104 KiB

strange_device

#include <bits/stdc++.h>
#define ll long long
#define lll __int128
#define endl "\n"
using namespace std;
int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    ll n, a, b;
    cin >> n >> a >> b;
    // a or b has certain pattern
    // ab -> 1 cycle, no duplikat
    // next cycle: sama persis
    // maintain cycles in terms of ab, merge all segments
    // find modulo ab
    // exist more than one cycle long -> all possible
    // size ab berarti diff >= ab - 1
    vector<pair<lll, bool>> sweep;
    ll ans = -1;
    for(int i = 1; i <= n; ++i) {
        ll l, r;
        cin >> l >> r;
        if(r - l >= (lll)1 * a * b) {
            ans = (lll)1 * a * b;
        }
        else {
            l %= (lll)1 * a * b;
            r %= (lll)1 * a * b;
            if(l <= r) {
                sweep.push_back(make_pair(l, 0));
                sweep.push_back(make_pair(r, 1));
            }
            else {
                sweep.push_back(make_pair(0, 0));
                sweep.push_back(make_pair(l, 0));
                sweep.push_back(make_pair((lll)a * b - 1, 1));
                sweep.push_back(make_pair(r, 1));
            }
        }
    }
    if(ans != -1)
        cout << ans << endl, exit(0);
    sort(sweep.begin(), sweep.end());
    int cnt = 0;
    ll st;
    ans = 0;
    for(auto i : sweep) {
        if(i.second) {
            // end
            --cnt;
            if(cnt == 0)
                ans += i.first - st;
        }
        else {
            // start
            // start itu + cnt
            // set start kalo belum di set
            if(cnt == 0)
                st = i.first - 1;
            ++cnt;
        }
    }
    cout << ans << endl;
}

Compilation message (stderr)

strange_device.cpp: In function 'int main()':
strange_device.cpp:51:32: warning: 'st' may be used uninitialized in this function [-Wmaybe-uninitialized]
   51 |                 ans += i.first - st;
      |                        ~~~~~~~~^~~~

• Subtask 1: 0 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 0 / 5
• Subtask 5: 0 / 5
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20
• Subtask 8: 0 / 30