| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1083984 | Tymond | Dreaming (IOI13_dreaming) | C++17 | 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>
#include "dreaming.h"
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
const int MAXN = 1e5 + 7;
vector<pii> g[MAXN];
int root[MAXN];
int parent[MAXN];
int mx[MAXN];
int best[MAXN];
int vis[MAXN];
int n, m, l;
int ans = 0;
void dfs(int v, int p){
root[v] = root[p];
parent[v] = p;
vi vec;
for(auto [u, c] : g[v]){
if(u == p){
continue;
}
dfs(u, v);
mx[v] = max(mx[v], mx[u] + c);
vec.pb(mx[u] + c);
}
if(sz(vec) <= 1){
return;
}
sort(all(vec));
reverse(all(vec));
ans = max(ans, vec[0] + vec[1]);
}
void dfs2(int v, int p, int k){
vi vec;
for(auto [u, c] : g[v]){
if(u != p){
vec.pb(mx[u] + c);
}
}
sort(all(vec));
reverse(all(vec));
for(auto [u, c] : g[v]){
if(u == p){
continue;
}
int g = k + c;
best[u] = max(mx[u], k + c);
if(mx[u] + c == vec[0]){
if(sz(vec) > 1){
best[u] = max(best[u], vec[1] + c);
g = max(g, vec[1] + c);
}
}else{
best[u] = max(best[u], vec[0] + c);
g = max(vec[0] + c);
}
dfs2(u, v, g);
}
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
n = N;
m = M;
l = L;
for(int i = 0; i < m; i++){
g[A[i]].pb({B[i], T[i]});
g[B[i]].pb({A[i], T[i]});
}
for(int i = 0; i < n; i++){
if(!vis[i]){
root[i] = i;
dfs(i, i);
best[i] = mx[i];
dfs2(i, i, 0);
}
}
pii naj = {1e9, 0};
for(int i = 0; i < n; i++){
if(naj.fi > best[i]){
naj.fi = best[i];
naj.se = i;
}
}
map<int, int> mn;
for(int i = 0; i < n; i++){
mn[i] = 1e9;
}
for(int i = 0; i < n; i++){
mn[root[i]] = min(mn[root[i]], best[i]);
}
if(m == n - 2){
int sec = 0;
for(auto ele : mn){
if(root[ele.fi] == ele.fi && ele.fi != root[naj.se]){
sec = ele.se;
}
}
ans = max(ans, sec + naj.fi + l);
return ans;
}
vi ok;
for(auto ele : mn){
if(root[ele.fi] == ele.fi && root[naj.se] != ele.fi){
ok.pb(ele.se);
}
}
sort(all(ok));
reverse(all(ok));
ans = max(ans, naj.fi + 2 * l + ok[0] + ok[1]);
return ans;
}