#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define int long long
#define in pair<int, int>
#define f first
#define s second
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
struct seg_tree
{
//range add range max.
vector<int> tree, lazy;
void init(int n)
{
tree.assign(4*n+2, 0);
lazy.assign(4*n+2, 0);
return;
}
void build(const vector<int> &a, int id, int l, int r)
{
int m = (l+r)/2;
if(l==r)
{
tree[id] = a[m];
return;
}
build(a, 2*id, l, m);
build(a, 2*id+1, m+1, r);
return;
}
void upd(int val, int ql, int qr, int id, int l, int r)
{
if(qr < l || r < ql)
return;
if(ql <= l && r <= qr)
{
tree[id]+=val;
lazy[id]+=val;
return;
}
int m = (l+r)/2;
upd(val, ql, qr, 2*id, l, m);
upd(val, ql, qr, 2*id+1, m+1, r);
tree[id] = max(tree[2*id], tree[2*id+1])+lazy[id];
return;
}
int query(int ql, int qr, int id, int l, int r)
{
if(qr < l || r < ql)
return 0;
if(ql <= l && r <= qr)
return tree[id];
int m = (l+r)/2;
int s1 = query(ql, qr, 2*id, l, m);
int s2 = query(ql, qr, 2*id+1, m+1, r);
return max(s1, s2);
}
};
const int MX = 1e5+5;
const int LOGM = 17;
vector<in> adj[MX];
vector<seg_tree> work;
int pa[MX], tin[LOGM][MX], tout[LOGM][MX], just[LOGM][MX];
vector<pair<in, int>> edge;
vector<bool> cut(MX);
vector<int> sz(MX);
int centh[MX], ctin[MX], ctout[MX];
int ans[MX];//ans[i] stores max path through vertex i, where i has least centh[i]
set<in> ANS;//stores the above in a pair format (for efficient updates etc)
set<in> help[MX];//stores the neighbour set per centroid vertex with maximum weights enabled.
void dfs(int u, int p)
{
sz[u] = 1;
for(auto [v, w]: adj[u])
{
if(cut[v])
continue;
if(v==p)
continue;
dfs(v, u);
sz[u]+=sz[v];
}
return;
}
int centroid(int u, int p, int SZ)
{
for(auto [v, w]: adj[u])
{
if(cut[v])
continue;
if(v==p)
continue;
if(2*sz[v] > SZ)
return centroid(v, u, SZ);
}
return u;
}
int centimer;
int centroid_decomposition(int u, int lvl)
{
dfs(u, 0);
int root = centroid(u, 0, sz[u]);
work[root].init(sz[u]);
cut[root] = 1; centh[root] = lvl; ctin[root] = ++centimer; sz[root] = sz[u];
for(auto [v, w]: adj[root])
{
if(cut[v])
continue;
int X = centroid_decomposition(v, lvl+1);
pa[X] = root;
}
ctout[root] = centimer;
return root;
}
int cendfs(int u, int p, int root, int &timer, vector<int> &ref, int VALUE)
{
int OPT = 0;
ref.pb(VALUE);
tin[centh[u]-centh[root]][u] = ++timer;
if((p != 0) && (p != root))
just[centh[u]-centh[root]][u] = just[centh[p]-centh[root]][p];
else
just[centh[u]-centh[root]][u] = u;
for(auto [v, w]: adj[u])
{
if(v==p)
continue;
if((ctin[v] < ctin[root]) || (ctout[v] > ctout[root]))
continue;
int WWW = cendfs(v, u, root, timer, ref, VALUE+w)+w;
if(u == root)
help[root].insert({WWW, v});
OPT = max(OPT, WWW);
}
tout[centh[u]-centh[root]][u] = timer;
return OPT;
}
void update(int root, int u, int val)
{
int D = centh[u]-centh[root];
int J = just[D][u];
int D_p = centh[J]-centh[root];
int NUM = work[root].query(tin[D_p][J], tout[D_p][J], 1, 1, sz[root]);
help[root].erase({NUM, J});
work[root].upd(val, tin[D][u], tout[D][u], 1, 1, sz[root]);
NUM = work[root].query(tin[D_p][J], tout[D_p][J], 1, 1, sz[root]);
help[root].insert({NUM, J});
return;
}
int upd(int i, int val)
{
auto [u, v] = edge[i].f;
int delta = val-edge[i].s;
edge[i] = {{u, v}, val};
int root = (centh[u] < centh[v])? u : v;
while(root)
{
if(tin[centh[u]-centh[root]][u] < tin[centh[v]-centh[root]][v])
swap(u, v);
update(root, u, delta);
ANS.erase({ans[root], root});
ans[root] = 0; auto it = help[root].end(); it--;
ans[root]+=((*it).f); it--; ans[root]+=((*it).f);
ANS.insert({ans[root], root});
root = pa[root];
}
auto itt = ANS.end(); itt--;
return (*itt).f;
}
signed main()
{
fast();
freopen("out.txt", "w", stdout);
int n, q, W;
cin >> n >> q >> W;
work.resize(n+1);
int m = n-1;
edge.resize(m);
vector<int> www(m);
for(int i = 0; i < m; i++)
{
int u, v, w;
cin >> u >> v >> w;
adj[u].pb({v, w}); adj[v].pb({u, w});
edge[i] = {{u, v}, w};
}
int root = centroid_decomposition(1, 1);
for(int i = 1; i <= n; i++)
{
ANS.insert({0, i});
help[i].insert({0, i});
help[i].insert({0, 0});//ensuring there's always two elements: itself and fake zero.
}
for(int u = 1; u <= n; u++)
{
int timer = 0;
vector<int> ref; ref.pb(0);
cendfs(u, 0, u, timer, ref, 0);
work[u].build(ref, 1, 1, sz[u]);
}
int lst = 0;
while(q--)
{
int d, val;
cin >> d >> val;
d+=lst; d%=m; val+=lst; val%=W; lst = upd(d, val);
cout << lst << "\n";
}
return 0;
}
Compilation message
diameter.cpp: In function 'int main()':
diameter.cpp:196:6: warning: unused variable 'root' [-Wunused-variable]
196 | int root = centroid_decomposition(1, 1);
| ^~~~
diameter.cpp:182:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
182 | freopen("out.txt", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
6 ms |
23388 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
6 ms |
23388 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
4 ms |
21340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
11 ms |
36696 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2331 ms |
168152 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
6 ms |
23388 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
