Submission #1095036

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095036		ro9669	Strange Device (APIO19_strange_device)	C++17	100 / 100	336 ms	69076 KiB

strange_device

#include <bits/stdc++.h>
#define fi first
#define se second
#define all(v) v.begin() , v.end()
#define sz(v) int(v.size())
#define unq(v) sort(all(v)); v.resize(unique(all(v)) - v.begin());
using namespace std;

typedef long long ll;
typedef pair<int , int> ii;
typedef pair<long long , int> lli;

const int maxN = int(2e6)+7;
const ll inf = ll(1e18)+7;

pair<ll , ll> p[maxN] , nxt_p[maxN];

void solve(){
    int n; ll a , b;
    cin >> n >> a >> b;
    for (int i = 1 ; i <= n ; i++) cin >> p[i].fi >> p[i].se;
    a /= __gcd(a , b + 1);
    if (inf / a < b){
        ll ans = 0;
        for (int i = 1 ; i <= n ; i++) ans += 1ll * (p[i].se - p[i].fi + 1);
        cout << ans << "\n";
    }
    else{
        ll x = a * b;
        int num = 0;
        for (int i = 1 ; i <= n ; i++){
            if (p[i].fi + x - 1 <= p[i].se){
                cout << x << "\n";
                return;
            }
            if (p[i].fi % x <= p[i].se % x){
                nxt_p[++num] = {p[i].fi % x , p[i].se % x};
            }
            else{
                nxt_p[++num] = {p[i].fi % x , x - 1};
                nxt_p[++num] = {0 , p[i].se % x};
            }
        }
        n = num;
        sort(nxt_p + 1 , nxt_p + n + 1);
        ll ans = 1ll * (nxt_p[1].se - nxt_p[1].fi + 1) , cur = nxt_p[1].se + 1;
        for (int i = 2 ; i <= n ; i++){
            if (max(cur , nxt_p[i].fi) <= nxt_p[i].se){
                ans += nxt_p[i].se - max(cur , nxt_p[i].fi) + 1;
                cur = nxt_p[i].se + 1;
            }
        }
        cout << ans << "\n";
    }
}

#define name "A"

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(name".INP" , "r")){
        freopen(name".INP" , "r" , stdin);
        freopen(name".OUT" , "w" , stdout);
    }
    int t = 1; //cin >> t;
    while (t--) solve();
    return 0;
}

Compilation message (stderr)

strange_device.cpp: In function 'int main()':
strange_device.cpp:62:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |         freopen(name".INP" , "r" , stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen(name".OUT" , "w" , stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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