Submission #403486

#	Time	Username	Problem	Language	Result	Execution time	Memory
403486		Hazem	Strange Device (APIO19_strange_device)	C++14	100 / 100	636 ms	49684 KiB

strange_device

#include <bits/stdc++.h>
using namespace std;
 
#define LL long long
#define F first
#define S second
#define pii pair<int,int>
#define piii pair<pair<int,int>,int>

const int N = 1e6+10;
const int M = 200;
const LL INF = 1e9;
const LL LINF = 2e18;
const LL MOD = 1e9+7;
const double PI = 3.141592653589793;

pair<LL,LL>p[N];
vector<pair<LL,LL>>vec;

LL gcd(LL a,LL b){return !b?a:gcd(b,a%b);}

int main(){

    //freopen("out.txt","w",stdout);

    LL n,a,b,Len;
    scanf("%lld%lld%lld",&n,&a,&b);

    // for(int i=0;i<=n;i++)
    //     printf("%d %d\n",(i+i/b)%a,i%b);

    LL g = gcd(a,b+1);
    a /= g;

    if(log(a)+log(b+1)>=log(LLONG_MAX))    
        Len = LINF;
    else 
        Len = a*(b+1)-a;

    bool q = 0;
    for(int i=1;i<=n;i++){

        scanf("%lld%lld",&p[i].F,&p[i].S);
        q |= p[i].S-p[i].F+1>=Len;

        p[i].F %= Len;p[i].S %= Len;

        if(p[i].S>=p[i].F)
            vec.push_back({p[i].F,p[i].S});
        else 
            vec.push_back({p[i].F,Len-1}),vec.push_back({0,p[i].S});
    }

    sort(vec.begin(),vec.end());
    
    LL l = 0,r = -1,ans = 0;
    vec.push_back({LINF,LINF});

    for(int i=0;i<vec.size();i++){
        
        if(vec[i].F>r)
            ans += r-l+1,l = vec[i].F,r = vec[i].S;
        else 
            r = max(r,vec[i].S);
    }

    printf("%lld\n",q?Len:ans);
}   

Compilation message (stderr)

strange_device.cpp: In function 'int main()':
strange_device.cpp:59:18: 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]
   59 |     for(int i=0;i<vec.size();i++){
      |                 ~^~~~~~~~~~~
strange_device.cpp:27:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     scanf("%lld%lld%lld",&n,&a,&b);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:43:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |         scanf("%lld%lld",&p[i].F,&p[i].S);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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