| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 564121 | tamthegod | Race (IOI11_race) | 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 "race.h"
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<stack>
#include<queue>
#include<string>
#include<string.h>
#include<cmath>
#include<vector>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<cstdio>
#include<bitset>
#include<chrono>
#include<random>
#include<ext/rope>
/* ordered_set
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
*/
#define int long long
#define pb push_back
#define fi first
#define se second
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 1e6 + 5;
const int mod = 1e9 + 7;
const ll oo = 1e18;
int n, k;
vector<pair<int, int>> adj[maxN];
int depth[maxN], lg[maxN];
int f[maxN][21];
int dp[maxN];
void Log()
{
for(int i=2; i<maxN; i++) lg[i] = lg[i / 2] + 1;
}
void predfs(int u, int par)
{
for(pair<int, int> a : adj[u])
{
int v = a.fi, w = a.se;
if(v == par) continue;
dp[v] = dp[u] + w;
depth[v] = depth[u] + 1;
f[v][0] = u;
for(int i=1; i<=lg[n]; i++)
f[v][i] = f[f[v][i - 1]][i - 1];
predfs(v, u);
}
}
int lca(int u, int v)
{
if(depth[u] < depth[v]) swap(u, v);
int k = depth[u] - depth[v];
for(int i=lg[n]; i>=0; i--)
{
if(k & (1 << i))
{
u = f[u][i];
k -= (1 << i);
}
}
if(u == v) return u;
for(int i=lg[n]; i>=0; i--)
{
if(f[u][i] != f[v][i])
{
u = f[u][i];
v = f[v][i];
}
}
return f[u][0];
}
int Kth_Ancestor(int u, int k)
{
for(int i=lg[n]; i>=0; i--)
{
if(k & (1 << i))
{
u = f[u][i];
k -= (1 << i);
}
}
return u;
}
int dist(int u, int v)
{
return dp[u] + dp[v] - 2 * dp[lca(u, v)];
}
int res = oo;
void dfs(int u, int par)
{
for(pair<int, int> a : adj[u])
{
int v = a.fi, w = a.se;
if(v == par) continue;
dfs(v, u);
}
int low = 1, high = depth[u], mid;
while(low <= high)
{
mid = (low + high) / 2;
int p = Kth_Ancestor(u, mid);
if(dist(u, p) >= k) high = mid - 1;
else low = mid + 1;
}
int p = Kth_Ancestor(u, low);
if(dist(u, p) == k) res = min(res, low);
}
int best_path(int N, int K, int H[][2], int L[])
{
n = N;
k = K;
for(int i=0; i<n; i++)
{
H[i][0]++;
H[i][1]++;
adj[H[i][0]].pb({H[i][1], L[i]});
adj[H[i][1]].pb({H[i][0], L[i]});
}
Log();
predfs(1, 0);
dfs(1, 0);
return res < oo ? res : -1;
}