Submission #914749

#	Time	Username	Problem	Language	Result	Execution time	Memory
914749		LOLOLO	Cities (BOI16_cities)	C++17	0 / 100	6074 ms	22512 KiB

cities

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

#define           f     first
#define           s     second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (int)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())

const int N = 2e5 + 10;
int p[N], sz[N];

int get(int a) {
    return p[a] ? get(p[a]) : a;
}

bool unite(int a, int b) {
    a = get(a), b = get(b);
    if (a == b)
        return 0;

    if (sz[a] < sz[b])
        swap(a, b);

    sz[a] += sz[b];
    p[b] = a;
    return 1;
}

vector < pair <int, int>> ed[N];
int sp[N][20], timer = 1, in[N], ou[N];
ll dep[N];

void dfs(int u, int v) {
    sp[u][0] = v;
    for (int i = 1; i < 20; i++)
        sp[u][i] = sp[sp[u][i - 1]][i - 1];

    in[u] = timer;
    for (auto x : ed[u]) {
        if (x.f == v)
            continue;

        dep[x.f] = dep[u] + x.s;
        dfs(x.f, u);
    }

    ou[u] = timer++;
}

bool anc(int a, int b) {
    return in[a] <= in[b] && ou[a] >= ou[b];
}

int lca(int a, int b) {
    if (anc(a, b))
        return a;

    if (anc(b, a))
        return b;

    for (int i = 19; i >= 0; i--) {
        if (anc(sp[a][i], b) == 0)
            a = sp[a][i];
    }

    return sp[a][0];
}

ll solve() {
    int n, k, m;
    cin >> n >> k >> m;

    vector <int> lst;
    for (int i = 0; i < k; i++) {
        int a;
        cin >> a;
        lst.pb(a);
    }

    vector < vector <int>> save;
    for (int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        save.pb({c, a, b});
    }

    sort(all(lst), [&](int a, int b) {return in[a] < in[b];});
    sort(all(save));

    for (auto x : save) {
        if (unite(x[1], x[2])) {
            ed[x[2]].pb({x[1], x[0]});
            ed[x[1]].pb({x[2], x[0]});
        }
    }

    dfs(1, 1);
    for (int i = 0; i < k - 1; i++) {
        lst.pb(lca(lst[i], lst[i + 1]));
    }

    uniquev(lst);
    sort(all(lst), [&](int a, int b) {return in[a] < in[b];});

    stack <int> st;
    ll ans = 0;

    for (auto x : lst) {
        if (st.empty()) {
            st.push(x);
            continue;
        }

        while (anc(st.top(), x) == 0) {
            st.pop();
        }


        ans += (dep[x] - dep[st.top()]);
        st.push(x);
    }

    return ans;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;

    while (t--) {
        //solve();
        cout << solve() << '\n';
    }

    return 0;
}

• Subtask 1: 0 / 22
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26