Submission #200524

#	Time	Username	Problem	Language	Result	Execution time	Memory
200524		HellAngel	Remittance (JOI19_remittance)	C++14	0 / 100	7 ms	380 KiB

remittance

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int maxn = 1000007;
int a[maxn], b[maxn], n;
struct cmp
{
    bool operator()(const pair<int, int> &a, const pair<int, int> &b)
    {
        if(a.first == b.first) return ::a[a.second] < ::a[b.second];
        return a.first < b.first;
    }
};
set<pair<int, int>, cmp> st;
void AnsNo()
{
    cout << "No";
    exit(0);
}
void AnsYes()
{
    cout << "Yes";
    exit(0);
}

void Change(int pos, int val)
{
    int npos = (pos + 1) % n;
    st.erase({a[pos] - b[pos], pos});
    st.erase({a[npos] - b[npos], npos});
    a[pos] -= 2 * val;
    if(a[pos] < 0) AnsNo();
    a[npos] += val;
    st.insert({a[pos] - b[pos], pos});
    st.insert({a[npos] - b[npos], npos});
}

int32_t main()
{
    auto start = chrono::steady_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if(fopen("test.inp", "r")) freopen("test.inp", "r", stdin);
    cin >> n;
    for(int i = 0; i < n; i++) cin >> a[i] >> b[i], st.insert({a[i] - b[i], i});
    while(true)
    {
        if(st.rbegin()->first < 0) AnsNo();
        if(st.rbegin()->first == 0)
        {
            if(st.begin()->first < 0) AnsNo();
            else AnsYes();
        } 
        Change(st.rbegin()->second, max(st.rbegin()->first / 2, 1ll));
    }
    auto finish = chrono::steady_clock::now();
    cerr << '\n'<< chrono::duration_cast<chrono::milliseconds>(finish - start).count();
}

Compilation message (stderr)

remittance.cpp: In function 'int32_t main()':
remittance.cpp:43:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     if(fopen("test.inp", "r")) freopen("test.inp", "r", stdin);
                                ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 40
• Subtask 3: 0 / 45