Submission #619341

#	Time	Username	Problem	Language	Result	Execution time	Memory
619341		maximath_1	Dynamic Diameter (CEOI19_diameter)	C++11	100 / 100	4670 ms	108056 KiB

diameter

#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

#define ll long long
const int MX = 1e5 + 69;
const int LG = 17;
const ll inf = 4e18 + 69;
#define ll long long
int n, q; ll wtwtwt;
vector<pair<pair<int, int>, ll> > edges;
vector<int> adj[MX];

struct SegmentTree{
	ll st[MX * 2], lz[MX * 2];

	#define cm (cl + cr) / 2
	#define lc nd + 1
	#define rc nd + 2 * (cm - cl + 1)

	inline void prop(int nd, int cl, int cr){
		if(lz[nd]){
			st[nd] += lz[nd];
			if(cl != cr){
				lz[lc] += lz[nd];
				lz[rc] += lz[nd];
			}
			lz[nd] = 0;
		}
	}

	inline void upd(int nd, int cl, int cr, int lf, int rg, ll vl){
		prop(nd, cl, cr);
		if(cr < lf || rg < cl) return;
		if(lf <= cl && cr <= rg){
			lz[nd] += vl;
			prop(nd, cl, cr);
			return;
		}

		upd(lc, cl, cm, lf, rg, vl);
		upd(rc, cm + 1, cr, lf, rg, vl);
		st[nd] = max(st[lc], st[rc]);
	}

	inline ll que(int nd, int cl, int cr, int lf, int rg){
		prop(nd, cl, cr);
		if(cr < lf || rg < cl) return -1;
		if(lf <= cl && cr <= rg) return st[nd];
		ll L = que(lc, cl, cm, lf, rg);
		ll R = que(rc, cm + 1, cr, lf, rg);
		return max(L, R);
	}
} st[LG];

struct SegmentTreeIterative{
	ll st[MX << 1];

	inline void upd(int ps, ll vl){
		for(ps += MX, st[ps] = vl, ps >>= 1; ps > 0; ps >>= 1) st[ps] = max(st[ps << 1], st[ps << 1 | 1]);
	}

	inline ll que(ll lf, ll rg){
		ll rs = 0ll;
		for(lf += MX, rg += MX + 1; lf < rg; lf >>= 1, rg >>= 1){
			if(lf & 1) rs = max(st[lf ++], rs);
			if(rg & 1) rs = max(rs, st[-- rg]);
		}
		return rs;
	}
} stdp;

bool vis[MX], dead[MX];
int sz[MX];
inline void dfssz(int nw, int bf){
	sz[nw] = 1;
	for(int nx : adj[nw]) if(nx != bf && !dead[nx]){
		dfssz(nx, nw);
		sz[nw] += sz[nx];
	}
}

int cent = -1, ccsz = 0;
inline void dfscent(int nw, int bf){
	for(int nx : adj[nw]) if(nx != bf && !dead[nx]) dfscent(nx, nw);
	if(cent == -1 && sz[nw] >= (ccsz + 1) / 2) cent = nw;
}

int layer = 0, tin[MX][LG], tim[LG], tout[MX][LG], rt[MX][LG], par[MX][LG], layer_id[MX];
inline void init(int nw, int bf){
	rt[nw][layer] = cent;
	tin[nw][layer] = ++ tim[layer];
	par[nw][layer] = bf;
	for(int nx : adj[nw]) if(nx != bf && !dead[nx]) init(nx, nw);
	tout[nw][layer] = tim[layer];
}

vector<pair<int, int> > adj_root[MX];

inline void findCentroid(int nw){
	dfssz(nw, 0);
	cent = -1, ccsz = sz[nw];
	dfscent(nw, 0);

	init(cent, 0); layer_id[cent] = layer;
	for(int nx : adj[cent]) if(!dead[nx])
		adj_root[cent].push_back({tin[nx][layer], nx});
	sort(adj_root[cent].begin(), adj_root[cent].end());

	dead[cent] = 1;
	for(int nx : adj[cent]) if(!dead[nx]){
		layer ++;
		findCentroid(nx);
		layer --;
	}
}

set<pair<ll, int> > dp[MX];

int main(){
	scanf("%d %d %lld", &n, &q, &wtwtwt);
	for(int i = 1; i < n; i ++){
		int u, v; ll w;
		scanf("%d %d %lld", &u, &v, &w);
		adj[u].push_back(v);
		adj[v].push_back(u);
		edges.push_back({{u, v}, w});
	}

	findCentroid(1);

	for(auto e : edges){
		int u = e.first.first, v = e.first.second; ll w = e.second;
		for(int j = 0; j < LG; j ++){
			if(rt[u][j] != rt[v][j]) break;
			if(tin[u][j] < tin[v][j]) swap(u, v);
			st[j].upd(1, 1, n, tin[u][j], tout[u][j], w);
		}
	}

	for(int i = 1; i <= n; i ++){
		for(pair<int, int> nx : adj_root[i])
			dp[i].insert({st[layer_id[i]].que(1, 1, n, tin[nx.second][layer_id[i]], tout[nx.second][layer_id[i]]), tin[nx.second][layer_id[i]]});

		ll res = 0ll;
		auto it = dp[i].end();
		for(int _ = 0; _ < 2; _ ++) if(it != dp[i].begin()){
			it = prev(it);
			res += (*it).first;
		}

		stdp.upd(i, res);
	}

	ll last_answer = 0ll;
	for(; q --;){
		int ee; ll wt; scanf("%d %lld", &ee, &wt);
		ee = (int)((ee + last_answer) % (n - 1));
		wt = (wt + last_answer) % wtwtwt;

		int u = edges[ee].first.first, v = edges[ee].first.second; ll wtchange = wt - edges[ee].second;

		for(int j = 0; j < LG; j ++){
			if(rt[u][j] != rt[v][j]) break;
			if(tin[u][j] < tin[v][j]) swap(u, v);
			int uid = lower_bound(adj_root[rt[u][j]].begin(), adj_root[rt[u][j]].end(), make_pair(tin[u][j] + 1, -1)) - adj_root[rt[u][j]].begin();
			int anc = adj_root[rt[u][j]][uid - 1].second;

			dp[rt[u][j]].erase(make_pair(st[j].que(1, 1, n, tin[anc][j], tout[anc][j]), tin[anc][j]));
			st[j].upd(1, 1, n, tin[u][j], tout[u][j], wtchange);
			dp[rt[u][j]].insert(make_pair(st[j].que(1, 1, n, tin[anc][j], tout[anc][j]), tin[anc][j]));

			ll res = 0ll;
			auto it = dp[rt[u][j]].end();
			for(int _ = 0; _ < 2; _ ++) if(it != dp[rt[u][j]].begin()){
				it = prev(it);
				res += (*it).first;
			}

			stdp.upd(rt[u][j], res);
		}

		edges[ee].second = wt;

		last_answer = stdp.que(1, n);
		printf("%lld\n", last_answer);
	}

	return 0;
}

Compilation message (stderr)

diameter.cpp: In function 'int main()':
diameter.cpp:121:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  121 |  scanf("%d %d %lld", &n, &q, &wtwtwt);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:124:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  124 |   scanf("%d %d %lld", &u, &v, &w);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:157:23: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  157 |   int ee; ll wt; scanf("%d %lld", &ee, &wt);
      |                  ~~~~~^~~~~~~~~~~~~~~~~~~~~

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