Submission #1095737

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095737		cpptowin	Trains (BOI24_trains)	C++17	100 / 100	333 ms	31116 KiB

Main

#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define int long long
#define inf (int)1e18
#define bitcount(x) __builtin_popcountll(x)
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
#define all(x) x.begin(), x.end()
#define ss(x) (int)x.size()
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}
using namespace std;
const int nsqrt = 580;
const int mod = 1e9 + 7;
void add(int &x, int k)
{
    x += k;
    x %= mod;
    if (x < 0)
        x += mod;
}
void del(int &x, int k)
{
    x -= k;
    x %= mod;
    if (x < 0)
        x += mod;
}
int n;
vi event[maxn];
int a[maxn], b[maxn];
int save[N][N];
int f[maxn];
void calc(int x)
{
    fo(i, 1, nsqrt)
    {
        add(f[x], save[i][x % i]);
    }
}
void bigup(int x)
{
    for (int i = x + a[x]; i <= min(n, x + b[x] * a[x]); i += a[x])
    {
        add(f[i], f[x]);
    }
}
void smallup(int x)
{
    add(save[a[x]][x % a[x]], f[x]);
    if (x + (b[x] + 1) * a[x] <= n)
        event[x + (b[x] + 1) * a[x]].pb(x);
}
void rev(int x)
{
    for (auto it : event[x])
    {
        del(save[a[it]][it % a[it]], f[it]);
    }
}
main()
{
#define name "trains"
    if (fopen(name ".inp", "r"))
    {
        freopen(name ".inp", "r", stdin);
        freopen(name ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n;
    fo(i, 1, n) cin >> a[i] >> b[i];
    f[1] = 1;
    fo(i, 1, n)
    {
        rev(i);
        calc(i);
        if (a[i] > nsqrt)
            bigup(i);
        else if (a[i] > 0)
            smallup(i);
    }
    int ans = 0;
    fo(i, 1, n) add(ans, f[i]);
    cout << ans;
}

Compilation message (stderr)

Main.cpp:91:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   91 | main()
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:96:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         freopen(name ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen(name ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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