#include <stdio.h>
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
#define ll long long
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ld long double
#define bug cout << "bug\n";
const ll maxn = 1e6 + 5, maxm = 2e2 + 1;
const ll mod = 1e9 + 7, inf = 1e9, block = 550, hb = 126067, base = 1000050017,
biginf = 5e18;
const ld eps = 1e-15;
using namespace std;
int n;
ll a, b, p;
ll l[maxn], r[maxn];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n >> a >> b;
a = a / gcd(a, b + 1);
if (a > 1e18 / b){
p = 1e18;
}
else{
p = a * b;
}
vector<pair<ll, ll>> v;
for (int i = 1; i <= n; ++i){
cin >> l[i] >> r[i];
ll x = l[i] % p;
ll y = r[i] % p;
if (r[i] - l[i] + 1 >= p){
cout << p;
exit(0);
}
if (x <= y){
v.pb(mp(x, y));
}
else{
v.pb(mp(x, p - 1));
v.pb(mp(0, y));
}
}
sort(v.begin(), v.end());
ll ans = 0, nxt = -1;
for (auto it : v){
ll lf = it.f, rg = it.s;
if (nxt < lf){
ans += rg - lf + 1;
nxt = rg;
}
else if (nxt <= rg){
ans += rg - nxt;
nxt = rg;
}
}
cout << ans;
}
Compilation message
strange_device.cpp: In function 'int main()':
strange_device.cpp:51:13: error: 'gcd' was not declared in this scope
51 | a = a / gcd(a, b + 1);
| ^~~
