Submission #398439

#	Time	Username	Problem	Language	Result	Execution time	Memory
398439		AKiko	Strange Device (APIO19_strange_device)	C++17	0 / 100	1850 ms	81164 KiB

strange_device

#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define ss second
#define ff first
#define pb push_back
#define pii pair<int, int>
#define INF INT_MAX
#define debug(n) cout << #n << " = " << n << "\n";
#define FAST ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

using namespace std;

const ll MOD = 1e9 + 7;

int main() {
    ll n, A, B, T, K;
    cin >> n >> A >> B;
    K = A / __gcd(B + 1, A);
    T = K * B;
    map<ll, ll> m;
    for(int i = 0; i < n; i++) {
        ll l, r;
        cin >> l >> r;
        if(r - l + 1 >= T) {
            cout << T << "\n";
            return 0;
        }
        if(r % T < l % T) {
            m[0]++;
            m[r % T + 1]--;
            m[l]++;
            m[T]--;
        } else {
            m[l % T]++;
            m[r % T + 1]--;
        }
    }
    ll prev = 0;
    vector<pair<ll, ll> > segments;
    for(auto el : m) {
        prev += el.ss;
        segments.pb({el.ff, prev});
    }

    ll ans = 0;
    for(int i = 0; i < int(segments.size() - 1); i++) {
        if(segments[i].ss > 0){
            ans += segments[i + 1].ff - segments[i].ff;
        }
    }

    cout << ans << "\n";

    return 0;
}

/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?)
    * do smth instead of nothing and stay organized
    * WRITE STUFF DOWN
    * DON'T GET STUCK ON ONE APPROACH
*/

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