Submission #753887

#	Time	Username	Problem	Language	Result	Execution time	Memory
753887		marvinthang	Dreaming (IOI13_dreaming)	C++17	100 / 100	94 ms	10640 KiB

dreaming

/*************************************
*    author: marvinthang             *
*    created: 06.06.2023 15:55:43    *
*************************************/

#include "dreaming.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    vector <vector <pair <int, int>>> adj(N);
    REP(i, M) {
        adj[A[i]].emplace_back(T[i], B[i]);
        adj[B[i]].emplace_back(T[i], A[i]);
    }
    vector <int> distu(N, -1), distv(N, -1);
    vector <int> f;
    int r = 0;
    REP(i, N) if (distu[i] == -1) {
        vector <int> ver;
        auto bfs = [&] (int s, vector <int> &dist, bool f = false) {
            queue <int> q;
            dist[s] = 0;
            q.push(s);
            int ma = s;
            while (!q.empty()) {
                int u = q.front(); q.pop();
                if (f) ver.push_back(u);
                if (dist[ma] < dist[u]) ma = u;
                for (auto [w, v]: adj[u]) if (dist[v] == -1) {
                    dist[v] = dist[u] + w;
                    q.push(v);
                }
            }
            return ma;
        };
        int u = bfs(i, distu, true);
        for (int x: ver) distu[x] = -1;
        int v = bfs(u, distu);
        bfs(v, distv);
        maximize(r, distu[v]);
        int mi = 1e9;
        for (int u: ver) minimize(mi, max(distu[u], distv[u]));
        f.push_back(mi);
    }
    if (M == N - 1) return r;
    int res = 1e9;
    sort(ALL(f));
    REP(i, f.size()) {
        vector <int> v {f[i]};
        REPD(j, f.size()) if (j != i) {
            v.push_back(f[j] + L);
            if (v.size() == 3) break;
        }
        sort(v.rbegin(), v.rend());
        minimize(res, v[0] + v[1]);
    }
    return max(r, res);
}

#ifdef LOCAL
#include <stdio.h>
#include <stdlib.h>
#include "dreaming.h"

#define fail(s, x...) do { \
        fprintf(stderr, s "\n", ## x); \
        exit(1); \
    } while(0)

#define MAX_N 100000

static int A[MAX_N];
static int B[MAX_N];
static int T[MAX_N];

int main() {
    int N, M, L, i;
    int res;

    FILE *f = fopen("dreaming.in", "r");
    if (!f)
        fail("Failed to open input file.");

    res = fscanf(f, "%d%d%d", &N, &M, &L);
    for (i = 0; i < M; i++)
        res = fscanf(f, "%d%d%d", &A[i], &B[i], &T[i]);
    fclose(f);

    int answer = travelTime(N, M, L, A, B, T);
    printf("%d\n", answer);

    return 0;
}
#endif

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23