#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define int long long
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
using namespace std;
void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e5 + 100, mxc = 105, inf = 1e18, MX = 1e5 + 10;
set <pair <int,int> > g[N];
int res=0,mx=0,va;
void dfs(int v,int par = -1,int dis = 0){
//cout << v <<"-"<< dis << endl;
if(dis>mx){
mx=dis;
va=v;
}
for(auto to:g[v]){
if(to.ss==par){
continue;
}
dfs(to.ss,v,dis+to.ff);
}
}
main(){
iostream::sync_with_stdio (false);
cin.tie(nullptr);
cout.tie(nullptr);
int n, q, W;
cin >> n >> q >> W;
vector <array<int, 3> > vp(n);
set <pair <int,int> > st;
for(int i = 0; i < n - 1; i++){
int a, b, c;
cin >> a >> b >> c;
g[a].insert({c, b});
g[b].insert({c, a});
st.insert({c, b});
vp[i] = {a, b, c};
}
int last = 0;
while(q--){
int d, e;
cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % W;
auto &[a, b, c] = vp[d];
if(b == 1)
swap(a, b);
g[a].erase({c, b});
g[b].erase({c, a});
st.erase({c, b});
g[a].insert({e, b});
g[b].insert({e, a});
vp[d][2] = e;
st.insert({e, b});
auto it = --st.end();
int res = it ->ff;
if(it != st.begin()){
it--;
cout << res + it ->ff << endl;
}else
cout << res << endl;
}
}
/*
* Before implementing the problem:
Do I understand the problem correctly?
Which places are tricky? What do I need to remember to implement them correctly?
Which place is the heaviest by implementation? Can I do it simpler?
Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
----------------------------------
If not AC:
Did you remember to do everything to handle the tricky places you thought about before?
Is the solution correct?
Do I understand the problem correctly?
----------------------------------
If you have a test on which the solution gives wrong answer:
Is the solution doing what it was supposed to do?
Is the problem in the code or in the idea?
*/
Compilation message
diameter.cpp:39:2: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
39 | main(){
| ^~~~
diameter.cpp: In function 'void fp(std::string)':
diameter.cpp:15:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:15:71: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
4956 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
4956 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
4956 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
5 ms |
5212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
422 ms |
27728 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
4956 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
