Submission #850731

#	Time	Username	Problem	Language	Result	Execution time	Memory
850731		Forested	Airplane (NOI23_airplane)	C++17	100 / 100	328 ms	24312 KiB

Main

#ifndef LOCAL
#define FAST_IO
#endif

// ============
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define OVERRIDE(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, m, n) for (i32 i = (i32)(m); i < (i32)(n); ++i)
#define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER(i, n) for (i32 i = (i32)(n) - 1; i >= 0; --i)
#define ALL(x) begin(x), end(x)

using namespace std;

using u32 = unsigned int;
using u64 = unsigned long long;
using i32 = signed int;
using i64 = signed long long;
using f64 = double;
using f80 = long double;

template <typename T>
using Vec = vector<T>;

template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

#ifdef INT128

using u128 = __uint128_t;
using i128 = __int128_t;

istream &operator>>(istream &is, i128 &x) {
    i64 v;
    is >> v;
    x = v;
    return is;
}
ostream &operator<<(ostream &os, i128 x) {
    os << (i64)x;
    return os;
}
istream &operator>>(istream &is, u128 &x) {
    u64 v;
    is >> v;
    x = v;
    return is;
}
ostream &operator<<(ostream &os, u128 x) {
    os << (u64)x;
    return os;
}

#endif

[[maybe_unused]] constexpr i32 INF = 1000000100;
[[maybe_unused]] constexpr i64 INF64 = 3000000000000000100;
struct SetUpIO {
    SetUpIO() {
#ifdef FAST_IO
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
#endif
        cout << fixed << setprecision(15);
    }
} set_up_io;
// ============

#ifdef DEBUGF
#else
#define DBG(x) (void)0
#endif

int main() {
    i32 n, m;
    cin >> n >> m;
    Vec<i32> a(n);
    REP(i, n) {
        cin >> a[i];
    }
    Vec<Vec<i32>> g(n);
    REP(i, m) {
        i32 u, v;
        cin >> u >> v;
        --u;
        --v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    const auto dijk = [&](i32 s) -> Vec<i32> {
        Vec<i32> dist(n, INF);
        priority_queue<pair<i32, i32>, Vec<pair<i32, i32>>, greater<>> pq;
        dist[s] = 0;
        pq.emplace(0, s);
        while (!pq.empty()) {
            auto [d, v] = pq.top();
            pq.pop();
            if (d > dist[v]) {
                continue;
            }
            for (i32 u : g[v]) {
                i32 t = d + max(a[u] - d, 1);
                if (chmin(dist[u], t)) {
                    pq.emplace(t, u);
                }
            }
        }
        return dist;
    };
    Vec<i32> dist0 = dijk(0), dist1 = dijk(n - 1);
    i32 ans = INF;
    REP(i, n) {
        chmin(ans, 2 * max(dist0[i], dist1[i]));
    }
    REP(u, n) {
        for (i32 v : g[u]) {
            chmin(ans, 2 * max(dist0[u], dist1[v]) + 1);
        }
    }
    cout << ans << '\n';
}

• Subtask 1: 22 / 22
• Subtask 2: 10 / 10
• Subtask 3: 31 / 31
• Subtask 4: 37 / 37