Submission #1261025

#	Time	Username	Problem	Language	Result	Execution time	Memory
1261025		vominhhuy123	Sightseeing (NOI14_sightseeing)	C++20	25 / 25	1193 ms	114572 KiB

sightseeing

#include <bits/stdc++.h>
#define fto(i, a, b) for (int i = (a); i <= (b); ++i)
#define fdto(i, b, a) for (int i = (b); i >= (a); --i)
#define N 500005
#define mod 1000000007

using namespace std;

struct Edge {
    int u, v, w;
};
int n, m, k, ans[N], p[N], sz[N];
vector<pair<int, int>> adj[N];
vector<Edge> edge;

int root(int u) {
    return p[u] != u ? p[u] = root(p[u]) : u;
}

bool join(int u, int v) {
    u = root(u), v = root(v);
    if (u == v) return false;
    if (sz[v] > sz[u]) swap(u, v);
    sz[u] += sz[v];
    p[v] = u;
    return true;
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (fopen("test.inp", "r")) {
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    cin >> n >> m >> k;
    fto(i, 1, n) p[i] = i, sz[i] = 1;
    fto(i, 1, m) {
        int u, v, w; cin >> u >> v >> w;
        edge.push_back({u, v, w});
    }
    sort(edge.begin(), edge.end(), [](Edge x, Edge y){
        return x.w > y.w;
    });
    for (Edge &p : edge) {
        int u = p.u, v = p.v, w = p.w;
        if (join(u, v)) {
            adj[u].emplace_back(v, w);
            adj[v].emplace_back(u, w);
        }
    }
    fto(i, 1, n) ans[i] = -1;
    queue<int> q;
    q.push(1);
    ans[1] = N+1;
    while (q.size()) {
        int u = q.front(); q.pop();
        for (pair<int, int> &p : adj[u]) if (ans[p.first] == -1) {
            ans[p.first] = min(ans[u], p.second);
            q.push(p.first);
        }
    }
    while (k--) {
        int x; cin >> x;
        cout << ans[x] << '\n';
    }
}

Compilation message (stderr)

sightseeing.cpp: In function 'int main()':
sightseeing.cpp:32:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sightseeing.cpp:33:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 6 / 6
• Subtask 4: 10 / 10