Submission #1262380

#	Time	Username	Problem	Language	Result	Execution time	Memory
1262380		yf_yusuf	Boat (APIO16_boat)	C++20	0 / 100	270 ms	16148 KiB

boat

//```//    YF YUSUF
#define YF ios_base::sync_with_stdio(0);cout.setf(ios::fixed);
#define YUSUF cout.precision(0);cout.tie(0);cin.tie(0);
// #include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cmath>
#include <numeric>
#include <queue>
#include <stack>
#include <cassert>
#include <climits>
#include <string>
#include <cstdlib>
#include <random>
#include <ctime>
using namespace std;
#ifdef YF_CHECK
	bool Output=1;
#else
	#pragma GCC optimize ("unroll-loops")
	#pragma GCC optimize ("inline")
	#pragma GCC optimize ("Ofast")
	#pragma GCC optimize ("O3")
	bool Output=0;
#endif
using ll   = long long;
using ld   = long double;
using sll  = set <ll>;
using vll  = vector <ll>;
using mll  = map <ll,ll>;
using pll  = pair <ll,ll>;
using vvl  = vector <vll>;
using vpll = vector <pll>;
template<class T>T MIN(T&a,T b){a=min(a,b);return a;}
template<class T>T MAX(T&a,T b){a=max(a,b);return a;}
#define all(a) a.begin(),a.end()
#define sgr v+v+1,(tl+tr)/2+1,tr
#define sgl v+v,tl,(tl+tr)/2
#define pb push_back
#define ins insert
#define S second
#define F first
mt19937_64 MT(time(0));
ll BP(ll a,ll b,ll mod=1e9+7){
	if(b==0)return 1;
	ll q=BP(a,b/2,mod);
	return ((q*q)%mod*(b%2?a:1ll))%mod;
}
ll f(ll x){return x*(x+1)/2;}
ll dup(ll a,ll b){return (a+b-1)/b;}
ll lcm(ll a,ll b){return a/__gcd(a,b)*b;}
ll invf(ll x){return (-1+sqrt(1+8*x))/2;}
const ll  mod=998244353;
const ll  INF=1e18;
const ll  inf=1e9+7;
const ll  N  =1e6+7;
// ll t[4*N];
// ll merge(ll a,ll b){
	// return (a+b)%inf;
// }
// void up(ll pos,ll x,ll v=1,ll tl=1,ll tr=n){
	// if(tl==tr){
		// t[v]+=x;
		// t[v]%=inf;
	// }
	// else{
		// ll tm=(tl+tr)/2;
		// if(pos<=tm)up(pos,x,sgl);
		// else up(pos,x,sgr);
		// t[v]=merge(t[v+v],t[v+v+1]);
	// }
// }
// ll get(ll l,ll r,ll v=1,ll tl=1,ll tr=n){
	// if(l > tr || tl > r)return 0;
	// if(l<= tl && tr<=r)return t[v];
	// ll tm=(tl+tr)/2;
	// return merge(get(l,r,sgl),get(l,r,sgr));
// }
const ll FN=1e6 + 7; ll FACT[FN], inv[FN], FMOD=inf;
ll PER(ll n,ll k){return FACT[n] *inv[n-k]%FMOD;}
ll CNK(ll n,ll k){return PER(n,k)*inv[k  ]%FMOD;}
ll slow_cnk(ll n,ll k){
	ll ans = 1;
	MIN(k, n-k);
	for(int i=1;i<=k;i++){
		ans = (ans * (n-k+i))%FMOD;
		ans = (ans * inv[i])%FMOD;
	}
	return ans;
}
ll get(ll l1,ll r1,ll l2,ll r2){
	MAX(l2, l1);
	MIN(r1, r2);
	
	if(l2 > r1 || l1 > r2 || l1 > r1 || l2 > r2	)return 0;
	// cout<<l1<<" "<<r1<<", "<<l2<<" "<<r2<<"\n";
	ll n = max(r1, r2) - max(l1, l2) + 1;
	ll k = min(r1, r2) - max(l1, l2);
	return slow_cnk(n, k);
}
void YF_MAIN(ll TEST){
	ll n;
	cin>>n;
	ll a[n+1]{},b[n+1]{};
	ll dp[n+1]{};
	ll sum = 0;
	for(int i=1;i<=n;i++){
		cin>>a[i]>>b[i];
		dp[i] = b[i] - a[i] + 1;
		for(int j=i-1;j>=1;j--){
			if(a[j] > b[i])continue;
			dp[i] += (b[i]-a[i]+1)*(b[j]-a[j]+1)-get(a[j], b[j], a[i], b[i]);
			dp[i] %= inf;
		}
		sum += dp[i];
		sum %= inf;
		// cout<<dp[i]<<" ";
	}
	// cout<<"\n";
	cout<<(sum + inf) % inf;
}
bool TECT=0;
bool OUTP=1;
ll lg(ll x){return (x ? 63 - __builtin_clzll(x) : -1);}
const ll SN=2e0 + 7; ll SM[SN];
void BEFORE(){
	for(ll i=2;i<SN;i++){
		if(SM[i])continue;
		for(ll j=i;j<SN;j+=i)
			MAX(SM[j],i);
	}
	FACT[0]=inv[0]=1;
	for(int i=1;i<FN;i++){
		FACT[i]=FACT[i-1]*i%FMOD;
		inv[i]=BP(i,FMOD-2,FMOD);
	}
}
signed main(){
	// freopen(("input.txt"),"r",stdin);freopen(("output.txt"),"w",stdout);
	if(OUTP){YF YUSUF}
	cout<<(0 && Output ? "\nYF_OUTPUT:\n\n" : "");
	int TEST=1;
	if(TECT)
		cin>>TEST;
	BEFORE();
	for(int T=1;T<=TEST;T++){
		// cout<<"Case "<<T<<": ";
		YF_MAIN(T);
		cout<<(T==TEST ? "" : "\n");
	}
	return 0;
} 
//```

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