Submission #419966

#	Time	Username	Problem	Language	Result	Execution time	Memory
419966		Return_0	Race (IOI11_race)	C++17	100 / 100	604 ms	38788 KiB

race

#include "race.h"

// #pragma GCC optimize("Ofast,unroll-loops")
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma,tune=native")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef int ll;
typedef long double ld;
typedef pair <ll, ll> pll;

#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
	const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1); cout.flush();
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< (x) << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()

cl inf = sizeof(ll) == 4 ? (1e9 + 10) : (3e18), mod = 1e9 + 7, MOD = 998244353;

template <class A,class B> ostream& operator << (ostream& out,const pair<A,B>&a){return out<<'('<<a.first<<", "<<a.second<<')';}
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
  out<< '['; for (int i = -1; ++i < int(a.size());) out<< a[i] << (i + 1 < int(a.size()) ? ", " : ""); return out<<']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;

cl mxn = 2e5 + 7, mxk = 1e6 + 7;

ll mn [mxk], sz [mxn], h [mxn], len [mxn], arr [mxn], ans, k, L, R;
vector <array <ll, 2>> adj [mxn];
bool visible [mxn], init;

void initialize () { init = true; memset(mn, 63, sizeof mn); }

ll plant (cl &v, cl &pr = -1) {
	sz[v] = 1;
	for (auto [u, w] : adj[v]) if (visible[u] && u != pr) sz[v] += plant(u, v);
	return sz[v];
}

inline ll find_centroid (ll v, cl &n, ll pr = -1) {
	for (ll i = 0; i < SZ(adj[v]); i++) {
		ll &u = adj[v][i][0];
		if (sz[u] << 1 > n && visible[u] && u != pr) pr = v, v = u, i = -1;
	}
	return v;
}

void dfs (cl &v, cl &pr) {
	if (len[v] > k) return;
	arr[R++] = v;
	ans = min(ans, h[v] + mn[k - len[v]]);
	for (auto [u, w] : adj[v]) if (visible[u] && u != pr) {
		h[u] = h[v] + 1; len[u] = len[v] + w;
		dfs(u, v);
	}
}

inline void upd () { for (; L < R; L++) { ll &v = arr[L]; mn[len[v]] = min(mn[len[v]], h[v]); } }
inline void rmv () { for (ll i = 0; i < R; i++) mn[len[arr[i]]] = inf; }

void centroid_decomposition (ll v = 0) {
	v = find_centroid(v, plant(v));
	L = 1; R = 1; arr[0] = v; h[v] = len[v] = 0; mn[0] = 0;
	for (auto [u, w] : adj[v]) if (visible[u]) {
		h[u] = 1; len[u] = w;
		dfs(u, v);
		upd();
	}
	rmv();
	visible[v] = false;
	for (auto [u, w] : adj[v]) if (visible[u]) centroid_decomposition(u);
}

int best_path(int N, int K, int H[][2], int L[]) {
	if (!init) initialize();
	ans = inf; k = K;
	for (ll i = 0; i < N; i++) adj[i].clear(), visible[i] = true;
	for (ll i = 0; i < N - 1; i++) adj[H[i][0]].push_back({H[i][1], L[i]}), adj[H[i][1]].push_back({H[i][0], L[i]});
	centroid_decomposition();
	if (ans >= inf) ans = -1;
	return ans;
}
/*

*/

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57