제출 #1166795

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1166795		CrabCNH	Evacuation plan (IZhO18_plan)	C++20	0 / 100	271 ms	69340 KiB

plan

#include <bits/stdc++.h>

#define task   "BriantheCrab"

#define int    long long
#define pii    pair <int, int>
#define fi     first
#define se     second
#define szf    sizeof
#define sz(s)  (int)((s).size())

using namespace std;

template <class T> void mini (T &t, T f) {if (t > f) t = f;}
template <class T> void maxi (T &t, T f) {if (t < f) t = f;}

const int maxN = 1e5 + 5;
const int LOG = 20;
const int inf = 1e18 + 7;
const int mod = 1e9 + 7;

struct Node {
    int u, dis;
    
    bool operator < (const Node& other) const {
        return dis > other.dis;
    }
};

int n, m, K;
int L[maxN], d[maxN], h[maxN];
int par[maxN], sz[maxN];
int mi[maxN][LOG], mn[maxN][LOG], up[maxN][LOG];
bool check[maxN];
vector <Node> adj[maxN];
vector <int> nAdj[maxN], spe;
vector <pii> all;

void multiSources () {
    priority_queue <Node> pq;
    for (int i = 1; i <= n; i ++) {
        L[i] = inf;
    }
    for (auto u : spe) {
        L[u] = 0;
        pq.push ({u, 0});
    }
    while (!pq.empty ()) {
        auto [u, c] = pq.top ();
        pq.pop ();
        if (c > L[u]) {
            continue;
        }
        for (auto [v, dis] : adj[u]) {
            if (L[v] > L[u] + dis) {
                L[v] = L[u] + dis;
                pq.push ({v, L[v]});
            }
        }
    }
}

void init () {
    for (int i = 1; i <= n; i ++) {
        par[i] = i;
        sz[i] = 1;
    }
}

int getRoot (int u) {
    if (par[u] == u) {
        return u;
    }
    return (par[u] = getRoot (par[u]));
}

void merge (int u, int v) {
    u = getRoot (u);
    v = getRoot (v);
    if (u == v) {
        return;
    }    
    if (sz[u] < sz[v]) {
        swap (u, v);
    }
    par[v] = u;
    sz[u] += sz[v];
    return;
}
    
void dfs (int u, int p) {
    up[u][0] = p;
    for (int j = 1; j < LOG; j ++) {
        up[u][j] = up[up[u][j - 1]][j - 1];
        mi[u][j] = min (mi[u][j - 1], mi[up[u][j - 1]][j - 1]);
    }
    for (auto v : nAdj[u]) {
        if (v == p) {
            continue;
        }
        h[v] = h[u] + 1;
        mi[v][0] = L[v];
        dfs (v, u);
    }
}
 
int LCA (int u, int v) {
    if (h[u] < h[v]) {
        swap (u, v);
    }
    int k = h[u] - h[v];
    int res = inf;
    for (int j = LOG - 1; j >= 0; j --) {
        if ((k >> j) & 1) {
            res = min (res, mi[u][j]);
            u = up[u][j];
        }
    }
    if (u == v) {
        return res;
    }
    for (int j = LOG - 1; j >= 0; j --) {
        if (up[u][j] != up[v][j]) {
            res = min ({res, mi[u][j], mi[v][j]});
            u = up[u][j];
            v = up[v][j];
        }
    }
    return min ({res, mi[u][0], mi[v][0]});
}

void solve () {
    cin >> n >> m;
    for (int i = 1; i <= m; i ++) {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back ({v, w});
        adj[v].push_back ({u, w});
    }
    cin >> K;
    for (int i = 1; i <= K; i ++) {
        int u;
        cin >> u;
        spe.push_back (u);
    }
    multiSources ();
        for (int i = 1; i <= n; i ++) {
        all.push_back ({L[i], i});
    }
    sort (all.rbegin (), all.rend ());
    init ();
    // for (int cc = 1; cc <= n; cc ++) {
        // cout << par[cc] << ' ';
    // }
    // cout << '\n';
    // for (int i = 1; i <= n; i ++) {
        // cout << L[i] << ' ';
    // }
    //cout << '\n';
    for (auto [_, u] : all) {
        check[u] = 1;
        for (auto [v, w] : adj[u]) {
            int rtU = getRoot (u);
            int rtV = getRoot (v);
            if (rtU == rtV || check[v] == 0) {
                continue;
            }
            merge (u, v);
            // for (int cc = 1; cc <= n; cc ++) {
                // cout << par[cc] << ' ';
            // }
            // cout << '\n';
            nAdj[u].push_back (v);
            nAdj[v].push_back (u);
            //cout << u << ' ' << v << ' ' << '\n';
        }
    }
    dfs (1, 0);
    int q;
    cin >> q;
    while (q --) {
        int u, v;
        cin >> u >> v;
        //cout << u << ' ' << v << ' ' << LCA (u, v) << '\n';
        cout << LCA (u, v) << '\n';
    }
    return;
}

signed main () {
    cin.tie (nullptr) -> sync_with_stdio (false);
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    int t = 1;
    //cin >> t;
    while (t --) {
        solve ();
    } 
    return 0;
}
// thfdgb

컴파일 시 표준 에러 (stderr) 메시지

plan.cpp: In function 'int main()':
plan.cpp:193:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  193 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:194:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  194 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46