Submission #538044

#	Time	Username	Problem	Language	Result	Execution time	Memory
538044		pavement	Swapping Cities (APIO20_swap)	C++17	100 / 100	429 ms	69872 KiB

swap

#include "swap.h"
#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;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
//#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef double db;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

int N, M, dep[300005], link[100005], rep[100005], sz[100005], ep[100005][2], anc[300005][25];
bool nc[300005];
iii T[200005];
vector<int> U, V, W, adj[300005];

int find(int x) {
	if (x == link[x]) return x;
	return link[x] = find(link[x]);
}

void unite(int a, int b) {
	int u = a, v = b;
	a = find(a);
	b = find(b);
	if (a == b) return;
	if (sz[b] > sz[a]) swap(a, b);
	sz[a] += sz[b];
	link[b] = a;
	nc[a] |= nc[b];
	if (!nc[a]) {
		if (u == ep[a][0] && v == ep[b][0]) {
			ep[a][0] = ep[a][1];
			ep[a][1] = ep[b][1];
		} else if (u == ep[a][0] && v == ep[b][1]) {
			ep[a][0] = ep[a][1];
			ep[a][1] = ep[b][0];
		} else if (u == ep[a][1] && v == ep[b][0]) {
			ep[a][1] = ep[b][1];
		} else if (u == ep[a][1] && v == ep[b][1]) {
			ep[a][1] = ep[b][0];
		} else {
			swap(u, v);
			if (u == ep[a][0] && v == ep[b][0]) {
				ep[a][0] = ep[a][1];
				ep[a][1] = ep[b][1];
			} else if (u == ep[a][0] && v == ep[b][1]) {
				ep[a][0] = ep[a][1];
				ep[a][1] = ep[b][0];
			} else if (u == ep[a][1] && v == ep[b][0]) {
				ep[a][1] = ep[b][1];
			} else if (u == ep[a][1] && v == ep[b][1]) {
				ep[a][1] = ep[b][0];
			} else {
				nc[a] = 1;
			}
		}
	}
}

void dfs(int n, int e = -1) {
	anc[n][0] = e;
	for (int i = 1; i <= 20; i++)
		if (anc[n][i - 1] != -1)
			anc[n][i] = anc[anc[n][i - 1]][i - 1];
	for (auto u : adj[n])
		if (u != e) {
			dep[u] = dep[n] + 1;
			dfs(u, n);
		}
}

int lca(int u, int v) {
	if (dep[u] < dep[v]) swap(u, v);
	for (int i = 20; i >= 0; i--)
		if (dep[u] - (1 << i) >= dep[v]) u = anc[u][i];
	if (u == v) return u;
	for (int i = 20; i >= 0; i--)
		if (anc[u][i] != anc[v][i]) {
			u = anc[u][i];
			v = anc[v][i];
		}
	return anc[u][0];
}

void init(int _N, int _M, vector<int> _U, vector<int> _V, vector<int> _W) {
	N = _N;
	M = _M;
	U = _U;
	V = _V;
	W = _W;
	memset(anc, -1, sizeof anc);
	for (int i = 0; i < M; i++)
		T[i] = mt(W[i], U[i], V[i]);
	for (int i = 0; i < N; i++) {
		link[i] = rep[i] = ep[i][0] = ep[i][1] = i;
		sz[i] = 1;
	}
	sort(T, T + M);
	for (int i = 0; i < M; i++) {
		tie(W[i], U[i], V[i]) = T[i];
		int a = rep[find(U[i])], b = rep[find(V[i])];
		if (a != b) {
			adj[N + i].pb(a);
			adj[N + i].pb(b);
		} else {
			nc[find(U[i])] = 1;
			adj[N + i].pb(a);
		}
		unite(U[i], V[i]);
		nc[N + i] = nc[find(U[i])];
		rep[find(U[i])] = N + i;
	}
	dfs(N + M - 1);
}

int getMinimumFuelCapacity(int X, int Y) {
	int w = lca(X, Y);
	if (nc[w]) return W[w - N];
	for (int i = 20; i >= 0; i--)
		if (anc[w][i] != -1 && !nc[anc[w][i]])
			w = anc[w][i];
	if (anc[w][0] == -1) return -1;
	w = anc[w][0];
	return W[w - N];
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 23 / 23
• Subtask 6: 27 / 27