Submission #1278382

#	Time	Username	Problem	Language	Result	Execution time	Memory
1278382		phuocrucpp	Tourism (JOI23_tourism)	C++20	28 / 100	5092 ms	46396 KiB

tourism

#include<bits/stdc++.h>
#define task "main"
#define endl '\n'
#define pb push_back
#define fi first
#define se second
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii, ii>
#define base 341
#define MASK(i) (1ll << i)
#define oo 1e18
using namespace std;
const int maxn = 1e5 + 5;
const int lg = 18;
int S = 320; 

int n, m, test, tin[maxn], timer, c[maxn], h[maxn], par[maxn][lg + 2], tour[maxn];
vector <int> g[maxn];

// ---- new globals for Euler+RMQ LCA ----
vector<int> euler;
int firstOcc[maxn];
vector<int> depthEuler;
vector<vector<int>> st;
vector<int> lg2;
int eulerLen = 0;
// ---------------------------------------

void dfs(int u, int p) {

    tin[u] = ++timer;
    tour[timer] = u;


    par[u][0] = (p == -1 ? u : p);

    firstOcc[u] = (int)euler.size();
    euler.push_back(u);
    depthEuler.push_back(h[u]);

    for (int x : g[u]) {
        if (x == p) continue;
        h[x] = h[u] + 1;
        par[x][0] = u;
        dfs(x, u);

        euler.push_back(u);
        depthEuler.push_back(h[u]);
    }
}

void build_rmq() {
    eulerLen = (int)euler.size();

    lg2.assign(eulerLen + 1, 0);
    for (int i = 2; i <= eulerLen; ++i) lg2[i] = lg2[i/2] + 1;

    int K = lg2[eulerLen] + 1;
    st.assign(K, vector<int>(eulerLen));
    for (int i = 0; i < eulerLen; ++i) st[0][i] = i;

    auto better = [&](int i, int j) {
        if (depthEuler[i] < depthEuler[j]) return i;
        else return j;
    };

    for (int k = 1; k < K; ++k) {
        int len = 1 << (k-1);
        for (int i = 0; i + (1<<k) <= eulerLen; ++i) {
            st[k][i] = better(st[k-1][i], st[k-1][i + len]);
        }
    }
}

int lca(int u, int v) {
    int L = firstOcc[u];
    int R = firstOcc[v];
    if (L > R) swap(L, R);
    int len = R - L + 1;
    int k = lg2[len];
    int i1 = st[k][L];
    int i2 = st[k][R - (1<<k) + 1];
    int idx = (depthEuler[i1] < depthEuler[i2]) ? i1 : i2;
    return euler[idx];
}

void prelca() {
    euler.clear();
    depthEuler.clear();

    timer = 0;
    h[1] = 0;
    dfs(1, -1);

    build_rmq();


    for (int j = 1; j <= lg; j++) {
        for (int i = 1; i <= n; i++) {
            par[i][j] = par[par[i][j-1]][j-1];
        }
    }
}

int dist(int l, int r) {
    return h[l] + h[r] - 2 * h[lca(l, r)];
}

struct pt{
    int l, r, id;
};
bool ss(pt a, pt b) {
    int ab = a.l / S;
    int bb = b.l / S;
    if (ab != bb) return a.l < b.l;
    if (ab & 1) return a.r > b.r; 
    return a.r < b.r;
}

bool vs[maxn];
long long sum = 0;
int res[maxn], cnt[maxn];

set<int> stt;

void add(int x) {
    cnt[x]++;
    if (cnt[x] > 1) return;

    auto pr = stt.insert(tin[x]);
    auto it = pr.first;
    auto itn = next(it);
    auto itp = (it == stt.begin() ? stt.end() : prev(it));

    if (itn != stt.end() && itp != stt.end()) {
        int t1 = tour[*itp], t2 = tour[*itn];
        sum += (long long)dist(t1, x) + (long long)dist(t2, x) - (long long)dist(t1, t2);
    }
    else if (itn != stt.end()) {
        int y = tour[*itn];
        sum += (long long)dist(x, y);
    }
    else if (itp != stt.end()) {
        int y = tour[*itp];
        sum += (long long)dist(x, y);
    }
}

void del(int x) {
    cnt[x]--;
    if (cnt[x] > 0) return;
    auto it = stt.find(tin[x]);
    auto itn = next(it);
    auto itp = (it == stt.begin() ? stt.end() : prev(it));
    if (itn != stt.end() && itp != stt.end()) {
        int t1 = tour[*itp], t2 = tour[*itn];
        sum -= (long long)dist(t1, x);
        sum -= (long long)dist(t2, x);
        sum += (long long)dist(t1, t2);

    }
    else if (itn != stt.end()) {
        int y = tour[*itn];
        sum -= (long long)dist(x, y);
    }
    else if (itp != stt.end()) {
        int y = tour[*itp];
        sum -= (long long)dist(x, y);
    }
    stt.erase(it);
}

int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    if(fopen(task".inp","r")) {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    cin >> n >> m >> test;
    for (int i = 1; i < n; i++) {
        int l, r;
        cin >> l >> r;
        g[l].pb(r); g[r].pb(l);
    }

    euler.reserve(2 * n);
    depthEuler.reserve(2 * n);
    prelca();
    for (int i = 1; i <= m; i++) cin >> c[i];
    S = max(1, (int)sqrt(m));

    vector <pt> query;
    for (int i = 1; i <= test; i++) {
        int l, r;
        cin >> l >> r;
        query.pb({l, r, i});
    }

    sort(query.begin(), query.end(), ss);

    int L = 1, R = 0;
    sum = 0;
    fill(cnt, cnt + n + 2, 0);
    stt.clear();

    for (auto q : query) {
        while(R < q.r) {
            R++;
            add(c[R]);
        }
        while(L > q.l){
            L--;
            add(c[L]);
        }
        while(R > q.r) {
            del(c[R]);
            R--;
        }
        while(L < q.l) {
            del(c[L]);
            L++;
        }

        int t1 = tour[*stt.begin()];
        int t2 = tour[*stt.rbegin()];
        long long total = sum + (long long)dist(t1, t2);
        res[q.id] = (int)(total / 2 + 1);
    }

    for (int i = 1; i <= test; i++) cout << res[i] << endl;
}

Compilation message (stderr)

tourism.cpp: In function 'int main()':
tourism.cpp:177:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  177 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
tourism.cpp:178:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  178 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 7
• Subtask 4: 18 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 41