Submission #1303578

#	Time	Username	Problem	Language	Result	Execution time	Memory
1303578		mingga	Tourism (JOI23_tourism)	C++20	100 / 100	406 ms	23912 KiB

tourism

// Author: caption_mingle
#include "bits/stdc++.h"

using namespace std;

#ifdef LOCAL
#include "D:/debug.h"
#define debug(...) cerr << "\033[35m" << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define ln "\n"
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define ll long long
const int mod = 1e9 + 7;
const int inf = 2e9;
const int N = 1e5 + 7;
int n, m, q, head[N], in[N], par[N], chain, chain_id[N], sz[N], timer;
int ans[N], c[N];

vector<pair<int, int>> ev[N];

vector<int> g[N];
void pre_dfs(int u, int p) {
	sz[u] = 1;
	for(int v : g[u]) {
		if(v == p) continue;
		par[v] = u;
		pre_dfs(v, u);
		sz[u] += sz[v];
	}
}

void hld(int u, int p) {
	chain_id[u] = chain;
	if(!head[chain]) head[chain] = u;
	in[u] = ++timer;
	int nxt = 0;
	for(int v : g[u]) {
		if(v == p) continue;
		if(sz[v] > sz[nxt]) nxt = v;
	}
	if(nxt) hld(nxt, u);
	for(int v : g[u]) {
		if(v == p or v == nxt) continue;
		chain++;
		hld(v, u);
	}
}

int st[N * 4], lazy[N * 4], bit[N];

void update(int u, int x) {
	for(; u <= m; u += (u & -u)) bit[u] += x;
}


int get(int u) {
	int ans = 0;
	for(; u > 0; u -= (u & -u)) ans += bit[u];
	return ans;
}

void push(int i) {
	if(lazy[i]) {
		for(int j = i * 2; j <= i * 2 + 1; j++) {
			st[j] = lazy[j] = lazy[i];
		}
		lazy[i] = 0;
	}
}

void update(int i, int l, int r, int u, int v, int x) {
	if(l > v or r < u) return ;
	if(u <= l and r <= v and (st[i] != -1 or l == r)) {
		if(st[i] != -1) update(st[i], -(r - l + 1));
		update(x, r - l + 1);
		st[i] = x;
		lazy[i] = x;
		return;
	}
	push(i);
	int m = (l + r) >> 1;
	update(i * 2, l, m, u, v, x);
	update(i * 2 + 1, m + 1, r, u, v, x);
	if(st[i * 2] == st[i * 2 + 1]) st[i] = st[i * 2];
	else st[i] = -1;
}

void update_path(int u, int v, int col) {
	while(chain_id[u] != chain_id[v]) {
		if(chain_id[u] > chain_id[v]) {
			int x = head[chain_id[u]];
			update(1, 1, n, in[x], in[u], col);
			u = par[x];
		} else {
			int x = head[chain_id[v]];
			update(1, 1, n, in[x], in[v], col);
			v = par[x];
		}
	}
	if(in[u] > in[v]) swap(u, v);
	update(1, 1, n, in[u], in[v], col);
}

signed main() {
	cin.tie(0) -> sync_with_stdio(0);
	#define task ""
	if(fopen(task ".INP", "r")) {
		freopen(task ".INP", "r", stdin);
		freopen(task ".OUT", "w", stdout);
	}
	cin >> n >> m >> q;
	for(int i = 1; i < n; i++) {
		int u, v; cin >> u >> v;
		g[u].pb(v);
		g[v].pb(u);
	}
	for(int i = 1; i <= m; i++) cin >> c[i];
	for(int i = 1; i <= q; i++) {
		int l, r; cin >> l >> r;
		ev[r].pb({l, i});
	}
	pre_dfs(1, 0);
	hld(1, 0);
	memset(st, -1, sizeof st);
	for(int i = 1; i <= m; i++) {
		int u = c[i];
		if(i > 1) update_path(c[i - 1], u, i - 1);
		update(1, 1, n, in[u], in[u], i);
		for(auto [l, id] : ev[i]) {
			ans[id] = get(m) - get(l - 1);
		}
	}
	for(int i = 1; i <= q; i++) cout << ans[i] << ln;
    cerr << "\nTime: " << clock() * 1000 / CLOCKS_PER_SEC;
}

Compilation message (stderr)

tourism.cpp: In function 'int main()':
tourism.cpp:115:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  115 |                 freopen(task ".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
tourism.cpp:116:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |                 freopen(task ".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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