Submission #933146

#	Time	Username	Problem	Language	Result	Execution time	Memory
933146		8pete8	Strange Device (APIO19_strange_device)	C++17	65 / 100	1107 ms	126104 KiB

strange_device

#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<unordered_map>
#include <queue>
#include<cstring>
#include<cassert>
#include<limits.h>
#include<cmath>
#include<set>
#include<numeric> //gcd(a,b)
#include<algorithm>
#include<bitset> 
#include<stack>
using namespace std;
#define ll long long
#define f first
#define endl "\n"
#define s second
#define pii pair<int,int>
#define pppiiii pair<pii,pii>
#define ppii pair<int,pii>
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define pb push_back
//#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-loops")
#define int long long
const int mod=1e9+7,mxn=2e5,lg=30,inf=1e18+1,minf=-1e18,Mxn=2e6,root=700;
void setIO(string name){
	ios_base::sync_with_stdio(0); cin.tie(0);		
	freopen((name+".in").c_str(),"r",stdin);		
	freopen((name+".out").c_str(),"w",stdout);	
}	 
map<int,int>mp;
int GCD(int x, int y)
{
    if (y == 0) return x;
    return GCD(y, x%y);
}
int32_t main(){
	fastio
	int n;cin>>n;
	int a,b;cin>>a>>b;
	int k;
	k=(a/GCD(a,b+1));
	int c=k/inf;
	if(c>b)k=inf;
	else k=k*b;
	mp[0]=0;
	mp[k-1]=0;
	//if(k<=0)assert(0);
	for(int i=0;i<n;i++){
		int l,r;cin>>l>>r;
		l=(l%k);
		r=(r%k);
		mp[l-1]+=0;
		mp[l]+=1;
		//if(l>=k||r>=k)assert(0);
		if(r+1<k)mp[r+1]-=1;
		mp[r]+=0;
		if(l>r)mp[0]+=1;
	}
	int sum=0,ans=0,last=-1;
	for(auto i:mp){
		//if(i.f>k)break;
		sum+=i.s;
		if(sum>0)ans+=i.f-last;
		last=i.f;
	}
	cout<<ans;


	/*
	observation:
	y=t mod b
	x=(t+(k*b)+[t/b]+k)%a
	x=t+t[t/b]%a
	(k*(b+1))%a==0
	case 1 : (b+1)%a==0 -> k can be anything -> if y equal is equal ->k==1
	case 2 : k%a==0 -> k=g(a) -> k is a multiple of a ->val jump every k*b
	*|k=lcm(a,b+1)/(b+1)|*
	considering 1 range l,r
	first occurance of y=t mod b
 
	if r-l+1>k then it will cover all k
 
	block of b (range where all y value will be distinct)
	|		|		|		|
	if(k==2)
	block will be (range where all (x,y) value will be distinct)
	|				|				|
	
	find ways to count x%(k) 
	in a given set of range l,r
	l,r will cover a range of block
	can use prefix sum??
	*/
}

Compilation message (stderr)

strange_device.cpp: In function 'void setIO(std::string)':
strange_device.cpp:37:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |  freopen((name+".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:38:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |  freopen((name+".out").c_str(),"w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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