Submission #619259

#	Time	Username	Problem	Language	Result	Execution time	Memory
619259		Zanite	Dynamic Diameter (CEOI19_diameter)	C++17	29 / 100	5094 ms	37076 KiB

diameter

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

#pragma GCC optimize("trapv")

using ll	= long long;
using pll	= pair<ll, ll>;
using Edge	= pair<ll, pll>;

#define fi	first
#define se	second

const int maxN	= 1e5 + 5;

const ll INF	= 1e18;

ll n, q, w;
set<pll> adj[maxN];
vector<Edge> edges;

ll dist[maxN], initDia[maxN], parent[maxN];
ll timer, tin[maxN], tout[maxN], byTin[maxN];

struct Segtree {
	ll sz;
	vector<ll> seg, lazy;

	Segtree(ll sz) : sz(sz) {
		seg = lazy = vector<ll>((sz << 2) + 1, 0);
	}

	void build(ll pos, ll l, ll r) {
		if (l > r) {return;}
		if (l == r) {
			seg[pos] = dist[byTin[l]];
			cerr << pos << ' ' << l << ' ' << byTin[l] << ' ' << dist[byTin[l]] << '\n';
			return;
		}

		ll m = (l+r) >> 1, lc = pos << 1, rc = lc | 1;
		build(lc, l, m);
		build(rc, m+1, r);
		seg[pos] = max(seg[lc], seg[rc]);
	}
	void build() {build(1, 1, sz);}

	void updateNode(ll pos, ll val) {
		seg[pos] += val;
		lazy[pos] += val;
	}

	void checkLazy(ll pos) {
		if (lazy[pos] != 0) {
			ll lc = pos << 1, rc = lc | 1;
			updateNode(lc, lazy[pos]);
			updateNode(rc, lazy[pos]);
			lazy[pos] = 0;
		}
	}

	void update(ll pos, ll l, ll r, ll ul, ll ur, ll val) {
		if (l > r || ul > ur || l > ur || ul > r) return;
		if (ul <= l && r <= ur) {updateNode(pos, val); return;}

		checkLazy(pos);

		ll m = (l+r) >> 1, lc = pos << 1, rc = lc | 1;
		update(lc, l, m, ul, ur, val);
		update(rc, m+1, r, ul, ur, val);
		seg[pos] = max(seg[lc], seg[rc]);
	}
	void update(ll ul, ll ur, ll val) {update(1, 1, sz, ul, ur, val);}

	ll query(ll pos, ll l, ll r, ll ul, ll ur) {
		if (l > r || ul > ur || l > ur || ul > r) return 0;
		if (ul <= l && r <= ur) return seg[pos];

		checkLazy(pos);

		ll m = (l+r) >> 1, lc = pos << 1, rc = lc | 1;
		return max(query(lc, l, m, ul, ur), query(rc, m+1, r, ul, ur));
	}
	ll query(ll ul, ll ur) {return query(1, 1, sz, ul, ur);}

	void print() {
		for (ll i = 1; i <= sz; i++) {
			cout << query(i, i) << ' ';
		}
		cout << '\n';
	}
} S(1), T(1);

void compute(ll cur) {
	ll cdist = S.query(tin[cur], tin[cur]);
	vector<ll> children(2, cdist);

	for (auto &[nxt, w] : adj[cur]) {
		children.push_back(S.query(tin[nxt], tout[nxt]));
	}
	sort(children.begin(), children.end());
	reverse(children.begin(), children.end());

	//for (auto i : children) {cout << i << ' ';} cout <<'\n';

	//cout << cur << ' ' << -T.query(cur, cur) + children[0] + children[1] - 2ll*cdist << '\n';
	T.update(cur, cur, -T.query(cur, cur) + children[0] + children[1] - 2ll*cdist);
}

#define debug(x) cout << #x << " = " << x << '\n'

void dfs(ll cur, ll par, ll cdist, ll pw) {
	//debug(cur);
	tin[cur] = ++timer;
	byTin[timer] = cur;
	parent[cur] = par;

	dist[cur] = cdist;
	S.update(tin[cur], tin[cur], cdist);

	adj[cur].erase({par, pw});

	for (auto &[nxt, w] : adj[cur]) {
		if (nxt == par) continue;
		dfs(nxt, cur, cdist+w, w);
	}
	compute(cur);

	tout[cur] = timer;
}

int main() {
	scanf("%lld %lld %lld", &n, &q, &w);
	for (ll a, b, c, i = 1; i < n; i++) {
		scanf("%lld %lld %lld", &a, &b, &c);

		adj[a].insert({b, c});
		adj[b].insert({a, c});
		edges.push_back({c, {a, b}});
	}

	S = T = Segtree(n);
	dfs(1, 0, 0, 0);

	for (auto &[w, p] : edges) {
		if (tin[p.fi] > tin[p.se]) {swap(p.fi, p.se);}
	}

	//S.print(); T.print();
	/*
	for (ll i = 1; i <= n; i++) {
		cout << i << ": ";
		for (auto &[j, k] : adj[i]) {
			cout << "{" << j << ", " << k << "} ";
		}
		cout << '\n';
	}
	*/

	ll last = 0;

	for (ll d, e, i = 1; i <= q; i++) {
		scanf("%lld %lld", &d, &e);
		d = (d + last) % (n - 1);
		e = (e + last) % w;

		//debug(d); debug(e);

		auto &[w, p] = edges[d];
		//debug(e-w);

		S.update(tin[p.se], tout[p.se], e-w);

		adj[p.fi].erase({p.se, w});

		edges[d].fi = e;
		adj[p.fi].insert({p.se, e});

		for (ll cur = p.fi; cur > 0; cur = parent[cur]) {
			//debug(cur);
			compute(cur);
		}
		//S.print(); T.print();

		last = T.query(1, n);
		printf("%lld\n", last);
	}
}

Compilation message (stderr)

diameter.cpp: In function 'int main()':
diameter.cpp:132:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |  scanf("%lld %lld %lld", &n, &q, &w);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:134:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  134 |   scanf("%lld %lld %lld", &a, &b, &c);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:162:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  162 |   scanf("%lld %lld", &d, &e);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 0 / 13
• Subtask 3: 0 / 7
• Subtask 4: 18 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 27