Submission #157154

#	Time	Username	Problem	Language	Result	Execution time	Memory
157154		fedoseevtimofey	Construction of Highway (JOI18_construction)	C++14	16 / 100	2071 ms	111180 KiB

construction

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 1e5 + 7;
vector <int> g[N];
int sz[N], st[N], en[N], par[N], in[N], out[N], h[N];

int A[N], B[N], C[N];
deque <pair <int, int>> col[N];

void dfs(int u = 0, int p = -1) {
    par[u] = p;
    for (int i = 0; i < g[u].size(); ++i) {
        if (g[u][i] == p) {
            g[u].erase(g[u].begin() + i);
            break;
        }
    }
    sz[u] = 1;
    for (int v : g[u]) {
        dfs(v, u);
        sz[u] += sz[v];
    }
    for (int i = 1; i < (int)g[u].size(); ++i) {
        if (sz[g[u][i]] > sz[g[u][0]]) swap(g[u][i], g[u][0]);
    }
}

vector <int> e;

int dfs_hld(int u = 0, int head = 0) {
    e.push_back(u);
    in[u] = (int)e.size() - 1;
    st[u] = head;
    if (par[u] != -1) h[u] = h[par[u]] + 1;
    else h[u] = 0;
    if (!g[u].empty()) {
        en[u] = dfs_hld(g[u][0], head);
        for (int i = 1; i < (int)g[u].size(); ++i) {
            dfs_hld(g[u][i], g[u][i]);
        }
    } else {
        en[u] = u;
    }
    out[u] = (int)e.size() - 1;
    return en[u];
}

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

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0); cout.setf(ios::fixed); cout.precision(20);
    #ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) cin >> C[i];
    for (int i = 0; i + 1 < n; ++i) {
        cin >> A[i] >> B[i];
        --A[i], --B[i];
        g[A[i]].push_back(B[i]);
        g[B[i]].push_back(A[i]);
    }
    dfs();
    dfs_hld();
    col[0].push_back({C[0], 0});
    for (int id = 0; id + 1 < n; ++id) {
        int ans = 0;
        int u = B[id];
        vector <pair <int, int>> hv;
        while (u != -1) {
            int pth = st[u];
            vector <pair <int, int>> cur;
            for (int i = 0; i < (int)col[pth].size(); ++i) {
                if (anc(col[pth][i].second, u)) {
                    cur.push_back({col[pth][i].first, h[col[pth][i].second] - (i == 0 ? h[pth] - 1: h[col[pth][i - 1].second])});
                } else {
                    cur.push_back({col[pth][i].first, h[u] - (i == 0 ? h[pth] - 1: h[col[pth][i - 1].second])});
                    break;
                }
            }
            reverse(cur.begin(), cur.end());
            for (auto p : cur) hv.push_back(p);
            while (!col[pth].empty() && anc(col[pth][0].second, B[id])) col[pth].pop_front();
            col[pth].push_front({C[B[id]], u});
            u = par[st[u]];
        }   
        reverse(hv.begin(), hv.end());
        for (int i = 0; i < hv.size(); ++i) {
            for (int j = i + 1; j < hv.size(); ++j) {
                if (hv[i].first > hv[j].first) ans += hv[i].second * hv[j].second;
            }
        }
        cout << ans << '\n';
    }
}   

Compilation message (stderr)

construction.cpp: In function 'void dfs(int, int)':
construction.cpp:17:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < g[u].size(); ++i) {
                     ~~^~~~~~~~~~~~~
construction.cpp: In function 'int main()':
construction.cpp:97:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < hv.size(); ++i) {
                         ~~^~~~~~~~~~~
construction.cpp:98:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j = i + 1; j < hv.size(); ++j) {
                                 ~~^~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 0 / 84