Submission #1272052

#	Time	Username	Problem	Language	Result	Execution time	Memory
1272052		quangminh412	Fire (BOI24_fire)	C++17	0 / 100	45 ms	82608 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 oo = 0x3f3f3f3f;
const int maxn = 2e5 + 1;
const int lim = 1e6 + 1;
const int maxbit = 20;

struct BinaryLifting
{
    int nxt[maxbit][lim], R[lim];

    BinaryLifting() { for (int i = 0; i < lim; i++) R[i] = -oo; }

    void add(int a, int b) { R[a] = max(R[a], b); }
    void proc()
    {
        for (int i = 1; i < lim; i++)
            R[i] = max(R[i], R[i - 1]);
        for (int i = 0; i < lim; i++)
            nxt[0][i] = R[i];
        for (int i = 1; i < maxbit; i++)
            for (int j = 0; j < lim; j++)
            {
                int mid = nxt[i - 1][j];
                nxt[i][j] = (mid != -oo ? nxt[i - 1][mid] : -oo);
            }
    }

    int query(int a, int b)
    {
        int res = 0;
        for (int i = 0; i < maxbit && a < b; i++)
            if (nxt[i][a] != -oo)
            {
                a = nxt[i][a];
                res += (1 << i);
            }
        return (a < b ? oo : res);
    }
};

int S[maxn], E[maxn];
BinaryLifting B;
vector<int> v;
int n, m, N;

void solve()
{
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        cin >> S[i] >> E[i];
        v.push_back(S[i]);
        v.push_back(E[i]);
    }
    v.push_back(0);
    v.push_back(m);
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
    N = (int)v.size();
    map<int, int> mp;
    for (int i = 0; i < N; i++)
        mp[v[i]] = i;
    for (int i = 1; i <= n; i++)
    {
        S[i] = mp[S[i]];
        E[i] = mp[E[i]];
        if (S[i] < E[i])
        {
            B.add(S[i], E[i]);
            B.add(S[i] + N, E[i] + N);
        } else
            B.add(S[i], E[i] + N);
    }

    B.proc();

    int res = oo;
    for (int i = 0; i < N; i++)
        res = min(res, B.query(i, i + N));

    cout << (res == oo ? -1 : res) << '\n';
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
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 + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 17
• Subtask 3: 0 / 9
• Subtask 4: 0 / 13
• Subtask 5: 0 / 21
• Subtask 6: 0 / 26