| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 619075 | HappyPacMan | Dynamic Diameter (CEOI19_diameter) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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];
unoredered_map<int,int> tin[maxn],tout[maxn],edgeRoot[maxn];
set<pair<ll,int> > bestEdge[maxn],result;
ll cost[maxn];
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];
}
}
}
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;
}
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]++;
}
}
}
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);
}
}
}
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;
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
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;
}
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]);
}
}
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));
}
}
int 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]){
bestEdge[it].erase(bestEdge[it].find(make_pair(qry(it,1,0,timer[it]-1,tin[it][edgeRoot[it][i]],tout[it][edgeRoot[it][i]]),edgeRoot[it][i])));
upd(it,1,0,timer[it]-1,tin[it][i],tout[it][i]-1,cost[i]);
bestEdge[it].insert(make_pair(qry(it,1,0,timer[it]-1,tin[it][edgeRoot[it][i]],tout[it][edgeRoot[it][i]]),edgeRoot[it][i]));
}
}
for(int i=0;i<n;i++){
if(bestEdge[i].size() > 1){
result.emplace((*prev(bestEdge[i].end())).first+(*prev(prev(bestEdge[i].end()))).first,i);
}else if(bestEdge[i].size()){
result.emplace((*prev(bestEdge[i].end())).first,i);
}else{
result.emplace(0,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];
for(int it : partOf[i]){
if(bestEdge[it].size() > 1){
result.erase(result.find(make_pair((*prev(bestEdge[it].end())).first+(*prev(prev(bestEdge[it].end()))).first,it)));
}else if(bestEdge[it].size()){
result.erase(result.find(make_pair((*prev(bestEdge[it].end())).first,it)));
}else{
result.erase(result.find(make_pair(0,it)));
}
bestEdge[it].erase(bestEdge[it].find(make_pair(qry(it,1,0,timer[it]-1,tin[it][edgeRoot[it][i]],tout[it][edgeRoot[it][i]]),edgeRoot[it][i])));
upd(it,1,0,timer[it]-1,tin[it][i],tout[it][i]-1,df);
bestEdge[it].insert(make_pair(qry(it,1,0,timer[it]-1,tin[it][edgeRoot[it][i]],tout[it][edgeRoot[it][i]]),edgeRoot[it][i]));
if(bestEdge[it].size() > 1){
result.emplace((*prev(bestEdge[it].end())).first+(*prev(prev(bestEdge[it].end()))).first,it);
}else if(bestEdge[it].size()){
result.emplace((*prev(bestEdge[it].end())).first,it);
}else{
result.emplace(0,it);
}
}
cost[i] = j;
last = (*prev(result.end())).first;
cout << (*prev(result.end())).first << "\n";
}
}