Submission #1287445

#	Time	Username	Problem	Language	Result	Execution time	Memory
1287445		quangminh412	Trains (BOI24_trains)	C++17	100 / 100	79 ms	4156 KiB

Main

/*
  Ben Watson

  Quang Minh MasterDDDDD
*/

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

#define ll long long

const string name = "test";

void solve();
signed main()
{
    if (fopen((name + ".inp").c_str(), "r"))
    {
        freopen((name + ".inp").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    solve();

    return 0;
}

// main program
const int maxn = 1e5 + 1;
const int mod = 1e9 + 7;
const int N = 317;

void sub(int &a, int b) { a -= b; if (a < 0) a += mod; }
void add(int &a, int b) { a += b; if (a >= mod) a -= mod; }

int d[maxn], x[maxn];
int save[N][N];
int n;

void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> d[i] >> x[i];

    vector<int> dp(n + 1, 0);
    dp[1] = 1;
    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> pq;
    for (int i = 1; i <= n; i++)
    {
        while (!pq.empty() && pq.top().first < i)
        {
            int idx = pq.top().second;
            pq.pop();
            sub(save[d[idx]][idx % d[idx]], dp[idx]);
        }
        for (int t = 1; t < N; t++)
            add(dp[i], save[t][i % t]);
        if (d[i] >= N)
        {
            for (int t = 1; t <= x[i]; t++)
            {
                int j = i + t * d[i];
                if (j > n)
                    break;
                add(dp[j], dp[i]);
            }
            continue;
        }
        if (d[i] == 0)
            continue;
        pq.push({i + 1ll * x[i] * d[i], i});
        add(save[d[i]][i % d[i]], dp[i]);
    }

    int res = 0;
    for (int i = 1; i <= n; i++)
        add(res, dp[i]);

    cout << res << '\n';
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:19:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |         freopen((name + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 13 / 13
• Subtask 3: 16 / 16
• Subtask 4: 34 / 34
• Subtask 5: 29 / 29