Submission #571456

#	Time	Username	Problem	Language	Result	Execution time	Memory
571456		bojackduy	Evacuation plan (IZhO18_plan)	C++14	100 / 100	714 ms	76828 KiB

plan

#include<iostream>
#include<queue>
#include<stack>
#include<algorithm>
#include<string.h>
#define task 
#define size() size() * 1ll 
#define all(x) (x).begin(), (x).end()
#define allr(x, sz) (x) + 1, (x) + 1 + sz
#define pb push_back
#define pii pair<int,int>
#define fi first
#define se second
#define MASK(x) (1LL<<(x))
#define BIT(x,i) (((x)>>(i))&1)
#define numbit(x) __builtin_popcountll(x)

using namespace std;

const int N = 1e6 + 1;
const int M = 1e3 + 1;
const long long mod = 1e9 + 7;
const long long oo = 1e18 + 7;

typedef vector<int> vi;
typedef vector<pii> vii;
typedef long long ll;

template<class t>
bool mini(t &x,t y) {
    if (x > y) {
       x = y;
       return 1;
    }
return 0;
}
template<class t>
bool maxi(t &x,t y) {
    if (x < y) {
       x = y;
       return 1;
    }
return 0;
}
void file() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    //freopen(task.in, r, stdin);
    //freopen(task.out, w, stdout);
return ;
}

int n, m, k, Q;
int v[N], cha[N], sub[N], h[N], heavy[N], head[N], pos[N], d[N];
vi adj[N];
vii a[N];
pii e[N];
struct DSU {
    int n;
    vi cha;
    DSU(const int &_n = 0): n(_n + 3), cha(_n + 7, -1) {}
    int root(int u) {
        return (cha[u] < 0 ? u : cha[u] = root(cha[u]));
    }
    bool join(int u, int v) {
        if ((u = root(u)) == (v = root(v))) return 0;
        if (cha[u] > cha[v]) swap(u, v);
        cha[u] += cha[v];
        cha[v] = u;
    return 1;
    }
};

struct IT {
    int n;
    vi st;
    IT(const int &_n = 0): n(_n + 1), st(4 * _n + 1, mod) {}
    void adj(int id, int l, int r, int i, int val) {
        if (i < l || r < i) return ;
        if (l == r) {
            st[id] = val;
        return ;
        }
        int mid = l + r >> 1;
        adj(id << 1, l, mid, i, val);
        adj(id << 1 | 1, mid + 1, r, i, val);
        st[id] = min(st[id << 1], st[id << 1 | 1]);
    }
    int get(int id, int l, int r, int u, int v) {
        if (v < l || r < u) return mod;
        if (u <= l && r <= v) return st[id];
        int mid = l + r >> 1;
    return min(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
    }
    void adj(int i, int val) {
        adj(1, 1, n, i, val);
    }
    int get(int u, int v) {
        return get(1, 1, n, u, v);
    }
}it;

void build_tree() {
    cin >> k;
    priority_queue<pii, vii, greater<pii>> q;
    for (int i = 1; i <= n; i++) d[i] = mod;
    for (int i = 1; i <= k; i++) {
        cin >> v[i];
        q.push(pii(0, v[i]));
        d[v[i]] = 0;
    }

    while (q.size()) {
        int u = q.top().se;
        int du = q.top().fi;
        q.pop();
        if (d[u] < du) continue ;
        for (auto v: a[u]) {
            if (mini(d[v.se], d[u] + v.fi)) {
                q.push(pii(d[v.se], v.se));
            }
        }
    }

    sort(e + 1, e + 1 + m, [&](const pii &x, const pii &y){
        return min(d[x.fi], d[x.se]) < min(d[y.fi], d[y.se]);
    });
    DSU dsu(n);
    for (int i = m; i >= 1; i--) {
        if (dsu.join(e[i].fi, e[i].se)) {
            adj[e[i].fi].pb(e[i].se);
            adj[e[i].se].pb(e[i].fi);
        }
    }
}

void dfs(int u, int chu) {
    cha[u] = chu;
    sub[u] = 1;
    int cmax = -1;
    for (auto v: adj[u]) if (v != chu) {
        h[v] = h[u] + 1;
        dfs(v, u);
        sub[u] += sub[v];
        if (maxi(cmax, sub[v])) {
            heavy[u] = v;
        }
    }
}

void hld(int u, int h) {
    head[u] = h;
    pos[u] = ++pos[0];
    it.adj(pos[0], d[u]);
    if (heavy[u]) hld(heavy[u], h);
    for (auto v: adj[u]) if (v != cha[u]) {
        if (v != heavy[u]) hld(v, v);
    }
}

int lca(int u, int v) {
    int res = mod;
    while (head[u] != head[v]) {
        if (h[head[u]] < h[head[v]]) swap(u, v);
        int x = head[u];
        mini(res, it.get(pos[x], pos[u]));
        u = cha[x];
    }
    if (h[u] < h[v]) swap(u, v);
    mini(res, it.get(pos[v], pos[u]));
return res;
}

void solve(int test = -1) {

    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int x, y, z;
        cin >> x >> y >> z;
        e[i] = pii(x, y);
        a[x].pb(pii(z, y));
        a[y].pb(pii(z, x));
    }

    build_tree();
    dfs(1, 1);
    it = IT(n);
    hld(1, 1);
    cin >> Q;
    while (Q--) {
        int s, t;
        cin >> s >> t;
        cout << lca(s, t) << '\n';
    }
}

int32_t main()  {
    file();
    int T = 1;
    // cin >> T;
    for (int i = 1; i <= T; i++) {
        solve(i);
    }
return 0;
}

Compilation message (stderr)

plan.cpp: In member function 'void IT::adj(int, int, int, int, int)':
plan.cpp:85:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   85 |         int mid = l + r >> 1;
      |                   ~~^~~
plan.cpp: In member function 'int IT::get(int, int, int, int, int)':
plan.cpp:93:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   93 |         int mid = l + r >> 1;
      |                   ~~^~~
plan.cpp: In function 'void build_tree()':
plan.cpp:7:23: warning: '*' in boolean context, suggest '&&' instead [-Wint-in-bool-context]
    7 | #define size() size() * 1ll
      |                       ^
plan.cpp:114:14: note: in expansion of macro 'size'
  114 |     while (q.size()) {
      |              ^~~~

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