Submission #153601

#	Time	Username	Problem	Language	Result	Execution time	Memory
153601		12tqian	Remittance (JOI19_remittance)	C++14	100 / 100	443 ms	56640 KiB

remittance

#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
template<class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const double PI = 4 * atan(1);

#define sz(x) (int)(x).size()
#define ll long long
#define ld long double
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair <int, int>
#define vi vector<int>
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define vpi vector<pair<int, int>>
#define vpd vector<pair<double, double>>
#define pd pair<double, double>

#define f0r(i,a) for(int i=0;i<a;i++)
#define f1r(i,a,b) for(int i=a;i<b;i++)

template<typename A, typename B> ostream& operator <<(ostream &cout, pair< A, B> const &p) {return cout << "(" << p.f << ", " << p.s << ")"; }
template<typename A> ostream& operator <<(ostream &cout, vector<A> const &v){
    cout <<"["; for(int i = 0; i<v.size(); i++) {if(i) cout <<", "; cout << v[i];} return cout << "]";
}
void fast_io(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
}
void io(string taskname){
    string fin = taskname + ".in";
    string fout = taskname + ".out";
    const char* FIN = fin.c_str();
    const char* FOUT = fout.c_str();
    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);
    fast_io();
}
const int MAX = 1e6 + 6;
const ll MOD = 1e9+7;
vector<ll> a;
vector<ll> d;
ll po[MAX];
inline ll neg(ll x, ll mod){
    return mod - x;
}
inline ll fix(ll x, ll mod){
    x = x%mod;
    x = (x+mod)%mod;
    return x;
}
///use mods less than 1e9 + 7
int n;

long long mulmod(long long a,
                            long long b,
                            long long mod)
{
    return (a*b)%mod;
}

ll modInverse(ll a, ll m)
{
    ll m0 = m;
    ll y = 0, x = 1;

    if (m == 1)
      return 0;

    while (a > 1)
    {
        // q is quotient
        ll q = a / m;
        ll t = m;

        // m is remainder now, process same as
        // Euclid's algo
        m = a % m, a = t;
        t = y;

        // Update y and x
        y = x - q * y;
        x = t;
    }

    // Make x positive
    if (x < 0)
       x += m0;

    return x;
}
ll check(ll mod){
    f0r(i, MAX){
        if(i == 0) po[i] = 1;
        else{
            po[i] = mulmod(po[i-1], 2, mod);
         //   po[i] %= mod;
        }
    }
    ll rhs = 0;
    for(int i = n-1; i>= 0; i--){
           // cout << po[i] << " " << fix(d[i], mod) + mod <<   " " << d[i]  << endl;
        ll add = mulmod(po[i], fix(d[i], mod), mod);
        rhs += add;
       // cout << add << endl;
        if(rhs>=mod)rhs-=mod;
    }
   // cout << rhs - mod << endl;
    ll x = mulmod(modInverse(fix(neg(po[n]-1, mod), mod), mod),rhs, mod);
    return (x%mod);
}
vector<ll> times;
int good = 0;
void upd(int id, int val){
    if(a[id]>= 2){
        if(a[id] + val<2){
            good--;
        }
    }
    else{
        if(a[id] + val >= 2) good++;
    }
    a[id] += val;
}
int main(){
    fast_io();
    cin >> n;
    int cnt = 0;
    f0r(i, n){
        ll ai, bi;
        cin >> ai >> bi;
        a.eb(ai);
        cnt += (bi == 0);
        d.eb(bi - ai);
    }
    if(cnt == n){
        cnt = 0;
        f0r(i, n) cnt += (a[i] == 0);
        if(cnt == n)cout << "Yes" << endl;
        else cout << "No" <<endl;
        return 0;
    }
   // cout << d << endl;
    ll x = check(MOD);
    times.eb(x);
    int cur = n-1;
    f0r(i, n-1){
        ll val = times[sz(times) - 1]*2 + d[cur];
        times.eb(val);
        cur--;
    }

    reverse(all(times));
    //cout << times << endl;
    f0r(i, n){
        int j = (i+1)%n;
        if(times[i] != times[j]*2 + d[j]){
            cout << "No" << endl;
            return 0;
        }
        if(fix(times[i], MOD) >= 1e12 || times[i]<0){
            cout << "No" << endl;
            return 0;
        }
    }

    cout << "Yes" << endl;
    return 0;
}

Compilation message (stderr)

remittance.cpp:1:0: warning: ignoring #pragma comment  [-Wunknown-pragmas]
 #pragma comment(linker, "/stack:200000000")
 
remittance.cpp: In function 'void io(std::__cxx11::string)':
remittance.cpp:50:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen(FIN, "r", stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~
remittance.cpp:51:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen(FOUT, "w", stdout);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 40 / 40
• Subtask 3: 45 / 45