Submission #92494

#	Time	Username	Problem	Language	Result	Execution time	Memory
92494		qkxwsm	Min-max tree (BOI18_minmaxtree)	C++14	100 / 100	565 ms	52460 KiB

minmaxtree

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

random_device(rd);
mt19937 rng(rd());
const long long FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();

struct custom_hash
{
	template<class T>
	unsigned long long operator()(T v) const
	{
		unsigned long long x = v;
		x += FIXED_RANDOM;
		// x += 11400714819323198485ull;
		// x = (x ^ (x >> 30)) * 13787848793156543929ull;
		x = (x ^ (x >> 27)) * 10723151780598845931ull;
		return x ^ (x >> 31);
	}
};

template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T, class U> using hash_table = gp_hash_table<T, U, custom_hash>;

template<class T>
T randomize(T mod)
{
	return (uniform_int_distribution<T>(0, mod - 1))(rng);
}
template<class T>
void readi(T &x)
{
	x = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
	{
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		x = x * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		x = -x;
	}
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int buf[20], n = 0;
	while(output)
	{
		buf[n] = ((output % 10));
		output /= 10;
		n++;
	}
	for (n--; n >= 0; n--)
	{
		putchar(buf[n] + '0');
	}
	return;
}
template<class T>
void ckmin(T &a, T b)
{
	a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
	a = max(a, b);
}
long long expo(long long a, long long e, long long mod)
{
	return ((e == 0) ? 1 : ((expo(a * a % mod, e >> 1, mod)) * ((e & 1) ? a : 1) % mod));
}
template<class T, class U>
void nmod(T &x, U mod)
{
	if (x >= mod) x -= mod;
}
template<class T>
T gcd(T a, T b)
{
	return (b ? gcd(b, a % b) : a);
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define DBG(x) cerr << #x << " = " << (x) << endl
#define SZ(x) ((int) ((x).size()))
#define FOR(i, a, b) for (auto i = (a), i##__end__ = (b); i < i##__end__; i++)
#define FORD(i, a, b) for (auto i = (a) - 1, i##__end__ = (b); i >= i##__end__; i--)
#define ALL(x) (x).begin(), (x).end()

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-9;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 400013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<ld> vd;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
typedef vector<pdd> vpd;

int N, Q, T, M;
vi edge[MAXN];
pii bound[MAXN];
int parent[MAXN];
int ancestor[25][MAXN];
pii dup[25][MAXN];
int st[MAXN], ft[MAXN], depth[MAXN];
int ans[MAXN];
bitset<MAXN> vis, VIS;

bool insubt(int u, int v)
{
	return (u == N) || (st[u] <= st[v] && st[v] <= ft[u]);
}
void dfs(int u)
{
	st[u] = ft[u] = T;
	T++;
	for (int v : edge[u])
	{
		if (v == parent[u]) continue;
		parent[v] = u;
		depth[v] = depth[u] + 1;
		dfs(v);
		ft[u] = ft[v];
	}
}
int lca(int u, int v)
{
	//how far up does v go before u
	if (insubt(v, u)) return -1;
	FORD(i, 20, 0)
	{
		if (!insubt(ancestor[i][v], u))
		{
			v = ancestor[i][v];
		}
	}
	return v;
}


bitset<MAXN> color, seen;
int V;
vector<int> edge1[MAXN];
int match[MAXN];

bool dfs1(int u)
{
	if (seen[u])
	{
		return false;
	}
	seen[u] = true;
	for (int v : edge1[u])
	{
		if (match[v] == -1 || dfs1(match[v]))
		{
			match[u] = v;
			match[v] = u;
			return true;
		}
	}
	return false;
}
int matching()
{
	int res = 0;
	for (int i = 0; i < V; i++)
	{
		match[i] = -1;
	}
	for (int i = 0; i < V; i++)
	{
		if (color[i])
		{
			continue;
		}
		seen.reset();
		if (dfs1(i))
		{
			res++;
		}
	}
	return res;
}
void addedge(int u, int v)
{
	// cerr << "addedge " << u << " -> " << v << endl;
	edge1[u].PB(v);
	edge1[v].PB(u);
}

int32_t main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	// cout << fixed << setprecision(10);
	// cerr << fixed << setprecision(10);
	// if (fopen("file.in", "r"))
	// {
	// 	freopen ("file.in", "r", stdin);
	// 	freopen ("file.out", "w", stdout);
	// }
	cin >> N;
	FOR(i, 0, N - 1)
	{
		int u, v; cin >> u >> v; u--; v--;
		edge[u].PB(v);
		edge[v].PB(u);
	}
	parent[0] = N; dfs(0);
	FOR(i, 0, 22)
	{
		ancestor[i][N] = N;
	}
	FOR(i, 0, N)
	{
		ancestor[0][i] = parent[i];
		dup[0][i] = {-INF, INF};
	}
	FOR(i, 1, 21)
	{
		FOR(j, 0, N)
		{
			ancestor[i][j] = ancestor[i - 1][ancestor[i - 1][j]];
			dup[i][j] = {-INF, INF};
		}
	}
	cin >> Q;
	while(Q--)
	{
		int u, v, val;
		char typ;
		cin >> typ >> u >> v >> val; u--; v--;
		if (typ == 'm')
		{
			int w = lca(u, v), diff = depth[v] - depth[w] + 1;
			if (w != -1)
			{
				int x = v;
				FORD(i, 20, 0)
				{
					if (diff & (1 << i))
					{
						ckmax(dup[i][x].fi, val);
						x = ancestor[i][x];
					}
				}
			}
			w = lca(v, u);
			if (w != -1)
			{
				int x = u, diff = depth[u] - depth[w] + 1;
				FORD(i, 20, 0)
				{
					if (diff & (1 << i))
					{
						ckmax(dup[i][x].fi, val);
						x = ancestor[i][x];
					}
				}
			}
		}
		if (typ == 'M')
		{
			int w = lca(u, v);
			if (w != -1)
			{
				int x = v, diff = depth[v] - depth[w] + 1;
				FORD(i, 20, 0)
				{
					if (diff & (1 << i))
					{
						ckmin(dup[i][x].se, val);
						x = ancestor[i][x];
					}
				}
			}
			w = lca(v, u);
			if (w != -1)
			{
				int x = u, diff = depth[u] - depth[w] + 1;
				FORD(i, 20, 0)
				{
					if (diff & (1 << i))
					{
						ckmin(dup[i][x].se, val);
						x = ancestor[i][x];
					}
				}
			}
		}
	}
	FORD(i, 20, 1)
	{
		FOR(j, 0, N)
		{
			ckmin(dup[i - 1][j].se, dup[i][j].se);
			ckmin(dup[i - 1][ancestor[i - 1][j]].se, dup[i][j].se);
			ckmax(dup[i - 1][j].fi, dup[i][j].fi);
			ckmax(dup[i - 1][ancestor[i - 1][j]].fi, dup[i][j].fi);
		}
	}
	FOR(i, 0, N)
	{
		bound[i] = dup[0][i];
		// cerr << bound[i].fi << ' ' << bound[i].se << endl;
	}
	vi compress;
	//you can have one or the other, but not both!
	FOR(i, 1, N)
	{
		compress.PB(bound[i].fi);
		compress.PB(bound[i].se);
	}
	compress.PB(-INF); compress.PB(INF);
	sort(ALL(compress));
	compress.erase(unique(ALL(compress)), compress.end());
	V = SZ(compress);
	// DBG(V);
	FOR(i, 1, N)
	{
		bound[i].fi = LB(ALL(compress), bound[i].fi) - compress.begin();
		bound[i].se = LB(ALL(compress), bound[i].se) - compress.begin();
		// cerr << bound[i].fi << ' ' << bound[i].se << endl;
	}
	FOR(i, 0, V) color[i] = 1;
	//you add an edge from x
	FOR(i, 1, N)
	{
		if (bound[i].fi != 0)
		{
			addedge(bound[i].fi, i + V - 1);
		}
		if (bound[i].se != V - 1)
		{
			addedge(bound[i].se, i + V - 1);
		}
	}
	V += (N - 1);
	int x = matching();
	V -= (N - 1);
	FOR(i, 1, V - 1)
	{
		ans[match[i] - (V - 1)] = i;
	}
	bitset<MAXN> VIS; VIS.reset();
	FOR(i, 1, N)
	{
		if (ans[i] == 0) ans[i] = bound[i].fi;
		VIS[ans[i]] = true;
	}
	FOR(i, 1, V - 1)
	{
		if (!VIS[i])
		{
			cout << "stupid\n";
			return 0;
		}
	}
	FOR(i, 1, N)
	{
		cout << i + 1 << ' ' << parent[i] + 1 << ' ' << compress[ans[i]] << '\n';
	}
	// cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}
/* READ READ READ
* int overflow, maxn too small, special cases (n=1?, two distinct?), cin.tie() interactive
* reread the problem, try small cases
* note down possible sources of error as you go
* do smth instead of nothing
*/

Compilation message (stderr)

minmaxtree.cpp: In function 'int32_t main()':
minmaxtree.cpp:393:6: warning: unused variable 'x' [-Wunused-variable]
  int x = matching();
      ^
minmaxtree.cpp:289:48: warning: array subscript is below array bounds [-Warray-bounds]
    int w = lca(u, v), diff = depth[v] - depth[w] + 1;
                                         ~~~~~~~^

• Subtask 1: 7 / 7
• Subtask 2: 22 / 22
• Subtask 3: 29 / 29
• Subtask 4: 42 / 42