Submission #619368

#	Time	Username	Problem	Language	Result	Execution time	Memory
619368		HappyPacMan	Dynamic Diameter (CEOI19_diameter)	C++17	49 / 100	5093 ms	487472 KiB

diameter

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")
using namespace std;
using ll = long long;
const int maxn = 1e5 + 3;
vector<pair<int,int> > adj[maxn],edges;
vector<int> partOf[maxn];
vector<ll> seg[maxn],lazy[maxn];
bool isCent[maxn];
int subSz[maxn],centRoot,timer[maxn],tinz[maxn],toutz[maxn];
unordered_map<int,int> tin[maxn],tout[maxn],edgeRoot[maxn];
unordered_map<int,ll> costEdge[maxn];
ll tempResult[maxn];
priority_queue<pair<ll,int> > bestEdge[maxn],result; 
ll cost[maxn];
 
inline void dfsSz(int u,int p){
	subSz[u] = 1;
	for(auto [v,w] : adj[u]){
		if(v != p && !isCent[v]){
			dfsSz(v,u);
			subSz[u] += subSz[v];
		}
	}
}
inline int fnCent(int u,int p,int s){
	for(auto [v,w] : adj[u]){
		if(v != p && !isCent[v] && subSz[v] > s/2){
			return fnCent(v,u,s);
		}
	}
	return u;
}
inline void dfsTour(int c,int u,int p){
	for(auto [v,w] : adj[u]){
		if(v != p && !isCent[v]){
			partOf[w].emplace_back(c);
			tin[c][w] = timer[c]++;
			dfsTour(c,v,u);
			tout[c][w] = timer[c]++;
		}
	}
}
inline void dfsEdgeRoot(int c,int d,int u,int p){
	for(auto [v,w] : adj[u]){
		if(v != p && !isCent[v]){
			edgeRoot[c][w] = d;
			dfsEdgeRoot(c,d,v,u);
		}
	}
}
inline void dfsCent(int u,int p){
	dfsSz(u,p);
	int cent = fnCent(u,u,subSz[u]);
	isCent[cent] = true;
	if(p != -1){
		centRoot = cent;
	}
	dfsTour(cent,cent,cent);
	for(auto [v,w] : adj[cent]){
		if(!isCent[v]){
			bestEdge[cent].emplace(0,w);
			edgeRoot[cent][w] = w;
			tinz[w] = tin[cent][w];
			toutz[w] = tout[cent][w];
			dfsEdgeRoot(cent,w,v,cent);
		}
	}
	seg[cent].resize(4*timer[cent]);
	lazy[cent].resize(4*timer[cent]);
	for(auto [v,w] : adj[cent]){
		if(!isCent[v]){
			dfsCent(v,cent);
		}
	}
}
 
// Segment Tree + Lazy Propagation
inline void push(int c,int i){
	lazy[c][i<<1] += lazy[c][i];
	seg[c][i<<1] += lazy[c][i];
	lazy[c][i<<1|1] += lazy[c][i];
	seg[c][i<<1|1] += lazy[c][i];
	lazy[c][i] = 0;
}
inline void upd(int c,int i,int l,int r,int ul,int ur,ll v){
	if(ul <= l && r <= ur){
		seg[c][i] += v;
		lazy[c][i] += v;
	}else if(ul > r || ur < l){
		return;
	}else{
		int m = (l+r)/2;
		push(c,i);
		upd(c,i<<1,l,m,ul,ur,v);
		upd(c,i<<1|1,m+1,r,ul,ur,v);
		seg[c][i] = max(seg[c][i<<1],seg[c][i<<1|1]);
	}
}
inline ll qry(int c,int i,int l,int r,int ql,int qr){
	if(ql <= l && r <= qr){
		return seg[c][i];
	}else if(ql > r || qr < l){
		return 0;
	}else{
		int m = (l+r)/2;
		push(c,i);
		return max(qry(c,i<<1,l,m,ql,qr),qry(c,i<<1|1,m+1,r,ql,qr));
	}
}
 
int32_t main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
 
	int n,q;
	ll w;
	cin >> n >> q >> w;
	for(int i=1;i<n;i++){
		int u,v;
		ll w;
		cin >> u >> v >> w;
		u--; v--;
		adj[u].emplace_back(v,i);
		adj[v].emplace_back(u,i);
		edges.emplace_back(u,v);
		cost[i] = w;
	}
	dfsCent(0,-1);
	for(int i=1;i<n;i++){
		for(int it : partOf[i]){
			int z = edgeRoot[it][i];
			upd(it,1,0,timer[it]-1,tin[it][i],tout[it][i]-1,cost[i]);
			costEdge[it][z] = qry(it,1,0,timer[it]-1,tinz[z],toutz[z]);
			bestEdge[it].emplace(costEdge[it][z],z);
		}
	}
	for(int i=0;i<n;i++){
		vector<pair<ll,int> > best;
		while(!bestEdge[i].empty() && best.size() < 2){
			auto [u,v] = bestEdge[i].top();
			bestEdge[i].pop();
			if(costEdge[i][v] == u && (best.empty() || best.back() != make_pair(u,v))){
				best.emplace_back(u,v);
			}
		}
		ll sum = 0;
		for(auto it : best){
			sum += it.first;
		}
		for(auto it : best){
			bestEdge[i].emplace(it);
		}
		tempResult[i] = sum;
		result.emplace(tempResult[i],i);
	}
	ll last = 0;
	while(q--){
		int i;
		ll j;
		cin >> i >> j;
		i = (i+last)%(n-1)+1;
		j = (j+last)%w;
		ll df = j-cost[i];
		assert(partOf[i].size() <= 20);
		for(int it : partOf[i]){
			int z = edgeRoot[it][i];
			upd(it,1,0,timer[it]-1,tin[it][i],tout[it][i]-1,df);
			costEdge[it][z] = qry(it,1,0,timer[it]-1,tinz[z],toutz[z]);
			bestEdge[it].emplace(costEdge[it][z],z);
			vector<pair<ll,int> > best;
			while(!bestEdge[it].empty() && best.size() < 2){
				auto [u,v] = bestEdge[it].top();
				bestEdge[it].pop();
				if(costEdge[it][v] == u && (best.empty() || best.back() != make_pair(u,v))){
					best.emplace_back(u,v);
				}
			}
			ll sum = 0;
			for(auto it2 : best){
				sum += it2.first;
			}
			for(auto it2 : best){
				bestEdge[it].emplace(it2);
			}
			tempResult[it] = sum;
			result.emplace(tempResult[it],it);
		}
		cost[i] = j;
		while(true){
			auto [u,v] = result.top();
			if(tempResult[v] == u){
				break;
			}
			result.pop();
		}
		last = result.top().first;
		cout << result.top().first << "\n";
	}
}

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