Submission #478127

#	Time	Username	Problem	Language	Result	Execution time	Memory
478127		nicolaalexandra	Remittance (JOI19_remittance)	C++14	100 / 100	896 ms	36412 KiB

remittance

#include <bits/stdc++.h>
#define DIM 1000010
using namespace std;

long long a[DIM],b[DIM],x[DIM],p[22];
int n,i;

int verif(){

    for (;;){
        int ok2 = 0;
        for (i=1;i<=n;i++){
            /// trimit cat de mult pot
            if (2 * x[i] <= a[i]){
                if (x[i])
                    ok2 = 1;
                a[i] -= 2 * x[i];
                a[ (i < n) ? (i+1) : (1)] += x[i];
                x[i] = 0;
            } else {
                long long val = a[i] / 2;
                if (val)
                    ok2 = 1;
                a[i] -= 2 * val;
                a[(i < n) ? (i+1) : (1)] += val;
                x[i] -= val;
            }
        }
        if (!ok2)
            break;
    }


    int ok = 1;
    for (i=1;i<=n;i++)
        if (x[i] != 0 || a[i] != b[i])
            ok = 0;

    return ok;
}

int main (){

    //ifstream cin ("date.in");
    //ofstream cout ("date.out");

    cin>>n;
    long long sum = 0, sum2 = 0;
    for (i=1;i<=n;i++){
        cin>>a[i]>>b[i];
        sum += a[i];
        sum2 += b[i];
    }

    if (!sum2){
        if (!sum)
            cout<<"Yes";
        else cout<<"No";

        return 0;
    }

    /// ce porcarie

    for (;;){
        int ok = 0;
        for (i=1;i<=n;i++){
            if (a[i] <= b[i])
                continue;

            long long val = (a[i] - b[i] + 1) / 2;

            if (val)
                ok = 1;

            a[i] -= 2*val;
            a[(i < n) ? (i+1) : (1)] += val;
        }
        if (!ok)
            break;
    }

    int ok = 1;
    for (i=1;i<=n;i++)
        if (a[i] != b[i]){
            ok = 0;
            break;
        }

    if (ok)
        cout<<"Yes";
    else cout<<"No";

    return 0;

    if (n == 2){

        long long val = a[1] - b[1] + 2 * (a[2] - b[2]);
        if (val % 3){
            cout<<"No";
            return 0;
        }

        x[2] = val / 3;

        if ( (a[1] - b[1] + x[2]) % 2){
            cout<<"No";
            return 0;
        }

        x[1] = (a[1] - b[1] + x[2]) / 2;

        if (x[1] < 0 || x[2] < 0){
            cout<<"No";
            return 0;
        }

        if (verif())
            cout<<"Yes";
        else cout<<"No";

        return 0;
    }

    p[0] = 1;
    for (i=1;i<=20;i++)
        p[i] = p[i-1] * 2;


    long long val = p[n-1] * (a[1] - b[1]) + p[n-2] * (a[n] - b[n]);
    for (i=n-1;i>=2;i--)
        val += p[i-2] * (a[i] - b[i]);

    if (val % (p[n]-1)){
        cout<<"No";
        return 0;
    }

    x[1] = val / (p[n]-1);

    if (val < 0){
        cout<<"No";
        return 0;
    }

    for (i=2;i<=n;i++){
        long long val = a[i] - b[i] + x[i-1];
        if (val % 2 || val < 0){
            cout<<"No";
            return 0;
        }
        x[i] = val / 2;
    }

    for (i=1;i<=n;i++){
        long long val = a[i] + x[ (i > 1) ? (i-1) : (n)  ] - 2 * x[i];
        if ( val != b[i] ){
            cout<<"No";
            return 0;
        }
    }


    if (verif())
        cout<<"Yes";
    else cout<<"No";


    return 0;
}

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