Submission #888791

#	Time	Username	Problem	Language	Result	Execution time	Memory
888791		vjudge1	Passport (JOI23_passport)	C++17	16 / 100	2067 ms	27244 KiB

passport

#include <bits/stdc++.h>
using namespace std;
typedef int64_t ll;
#define all(x) x.begin(), x.end()
#define size(x) (int)x.size()

template<class S, class T> 
bool chmin(S &a, const T &b) {
    return (a > b ? (a = b) == b : false);
}
template<class S, class T> 
bool chmax(S &a, const T &b) {
    return (a < b ? (a = b) == b : false);
}
const int inf = 1e9;
const ll INF = 1e18;
const int mod = 998244353;
const int N =  2500;

int n, l[N * 100], r[N * 100];
vector<vector<int>> d(N, vector<int> (N, inf));

void bfs(int init) {
    queue<pair<int, int>> q;
    d[l[init]][r[init]] = 1;
    q.push({l[init], r[init]});
    while (!q.empty()) {
        int L = q.front().first, R = q.front().second;
        q.pop();
        for (int i = L; i <= R; ++i) {
            int new_l = min(L, l[i]), new_r = max(R, r[i]);
            if (chmin(d[new_l][new_r], d[L][R] + 1)) {
                q.push({new_l, new_r});
            }
        }
    }
}

signed main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> l[i] >> r[i];
        l[i]--, r[i]--;
    }
    int q, x;
    cin >> q >> x;
    if (n <= 2500) {
        bfs(--x);
        cout << (d[0][n - 1] == inf ? -1 : d[0][n - 1]);
    } else {
        vector<int> dp(n + 1, inf);
        dp[0] = 1;
        int R = r[0], last = 0;
        for (int i = 0; i < n; ++i) {
            int k = R;
            for (int j = i; j <= R; ++j) {
                dp[j] = dp[last];
                chmax(k, r[j]);
            }
            dp[R + 1] = dp[last] + 1;
            last = R + 1;
        }
        cout << dp[n - 1];
    }
}

• Subtask 1: 0 / 6
• Subtask 2: 16 / 16
• Subtask 3: 0 / 24
• Subtask 4: 0 / 8
• Subtask 5: 0 / 46