Submission #71911

#	Time	Username	Problem	Language	Result	Execution time	Memory
71911		Good	Min-max tree (BOI18_minmaxtree)	C++11	22 / 100	494 ms	31572 KiB

minmaxtree

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

#define ff first
#define ss second
#define Maxn 70009
#define ll long long
#define pb push_back
#define Inf 1000000009
#define ppb() pop_back()
#define pii pair <int , int>
#define mid(x, y) (x + y) / 2
#define all(x) x.begin(),x.end()
#define llInf 1000000000000000009
#define tr(i, c) for(__typeof(c).begin() i = (c).begin() ; i != (c).end() ; i++)
using namespace std;
using namespace __gnu_pbds;
typedef tree <int, null_type, less <int>, rb_tree_tag, tree_order_statistics_node_update> order;

bool vis[Maxn];
bool vis1[Maxn];

int n, q;
int B[Maxn];
int cnt[Maxn];
int lvl[Maxn];
int E[Maxn][2];
int P[Maxn][2];
int mat[Maxn][20];

vector <int> T;
vector <int> S[Maxn];
vector <int> L[Maxn];
vector <int> adj[Maxn];
vector <pair <int, pair <int, pii> > > A[2];

map <int, int> mp;
map <pii, int> mp1;

void dfs (int nd, int p, bool d) {
	mat[nd][0] = p;
	lvl[nd] = lvl[p] + 1;
	
	for (auto i: adj[nd])
		if (i != p) {
			if (d == 1) {	
				cnt[E[i][0]] ++;
				if (E[i][1] != -1 and E[i][0] != -1)
					T.pb (E[i][0]), L[E[i][0]].pb (E[i][1]);	
					
				else if (E[i][0] == -1) {
					vis1[E[i][1]] = 1;
					mp1[{E[i][0], E[i][1]}] = 1;
				}	
			}
					
			dfs (i, nd, d);
		}	
}

void dfs1 (int nd, int p) {
	for (auto i: adj[nd]) {
		if (i != p) {
			if (mp1[{E[i][0], E[i][1]}]) {
				printf ("%d %d %d\n", nd, i, B[E[i][1]]); 
				if (E[i][0] != -1)
					mp1[{E[i][0], E[i][1]}] = 0;
			}	
				
			else 
				printf ("%d %d %d\n", nd, i, B[E[i][0]]);
						
			dfs1 (i, nd);	
		}
	}
}

void build () {
	for (int i = 1; i <= 18; i++)
		for (int j = 1; j <= n; j++)
			if (mat[j][i - 1] != -1)
				mat[j][i] = mat[mat[j][i - 1]][i - 1];	
}

int LCA (int a, int b) {
	if (lvl[a] < lvl[b])
		swap (a, b);
		
	for (int i = 18; i >= 0; i--)
		if (lvl[mat[a][i]] >= lvl[b])
			a = mat[a][i];
	
	if (a == b)
		return a;
	
	for (int i = 18; i >= 0; i--)
		if (mat[a][i] != -1 and mat[a][i] != mat[b][i])
			a = mat[a][i], b = mat[b][i];
		
	return mat[a][0];					
}

int dsu (int x, bool d) {
	if (P[x][d] == x)
		return x;	
	
	return P[x][d] = dsu (P[x][d], d);	
}

void solve (int x, int y, int z, bool d) {
	x = dsu (P[x][d], d);
			
	if (lvl[x] <= lvl[y])
		return;		
	
	E[x][d] = z;
	
	if (mat[x][0] != -1)
		P[x][d] = dsu (mat[x][0], d);
	
	x = P[x][d];
	solve (x, y, z, d);	
}

void solve1 (int ind) {
	int sm = 0;
	for (auto i: L[T[ind]])
		sm += !vis1[i];	
		
	if (sm < cnt[T[ind]]) {
		vis[ind] = 1;
		for (auto i: L[T[ind]])
			if (!vis1[i])
				vis1[i] = 1, mp1[{T[ind], i}] = 1;
		
		for (auto i: L[T[ind]]) {
			while (S[i].size() > 0) {
				int x = S[i].back();
				S[i].ppb();
				if (!vis[x])
					solve1 (x);
			}	
		}		
	}
	
	else
		for (auto i: L[T[ind]])
			if (!vis1[i])
				S[i].pb (ind);			
}

int main () {
	//freopen ("file.in", "r", stdin);
	//freopen ("file.out", "w", stdout);
	
 	//srand ((unsigned) time ( NULL ));
	//int randomNumber = rand() % 10 + 1;

	scanf ("%d", &n);
	for (int i = 1; i < n; i++) {
		int u, v;
		scanf ("%d%d", &u, &v);
		
		adj[u].pb (v);
		adj[v].pb (u);
		P[i][0] = P[i][1] = i;
	}
	
	P[n][0] = P[n][1] = n;
	
	memset (mat, -1, sizeof (mat));
	dfs (1, -1, 0);
	build ();
	
	scanf ("%d", &q);
	
	for (int i = 1; i <= q; i++) {
		char c;
		int x, y, z;
		
		scanf (" %c%d%d%d", &c, &x, &y, &z);
		mp[z] = 1;
		
		int l = LCA (x, y);
															
		if (c == 'M')
			A[0].pb ({z, {l, {x, y}}});
		else
			A[1].pb ({z, {l, {x, y}}});		
	}
	
	memset (E, -1, sizeof (E));
	
	int c = 1;
	for (auto i: mp)
		B[c] = i.ff, mp[i.ff] = c++;		
	
	sort (all (A[0]));
	sort (all (A[1]));
	reverse (all (A[1]));
	
	for (auto i: A[0]) {
		solve (i.ss.ss.ff, i.ss.ff, mp[i.ff], 0);
		solve (i.ss.ss.ss, i.ss.ff, mp[i.ff], 0);	
	}
		
	for (auto i: A[1]) {
		solve (i.ss.ss.ff, i.ss.ff, mp[i.ff], 1);
		solve (i.ss.ss.ss, i.ss.ff, mp[i.ff], 1);
	}
	
	dfs (1, -1, 1);
	T.erase (unique (all (T)), T.end());
	
	for (int i = 0; i < T.size(); i++)
		if (!vis[i])
			solve1 (i);
	
	dfs1 (1, -1);		
	return 0;
}

Compilation message (stderr)

minmaxtree.cpp: In function 'int main()':
minmaxtree.cpp:215:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < T.size(); i++)
                  ~~^~~~~~~~~~
minmaxtree.cpp:159:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d", &n);
  ~~~~~~^~~~~~~~~~
minmaxtree.cpp:162:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf ("%d%d", &u, &v);
   ~~~~~~^~~~~~~~~~~~~~~~
minmaxtree.cpp:175:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d", &q);
  ~~~~~~^~~~~~~~~~
minmaxtree.cpp:181:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf (" %c%d%d%d", &c, &x, &y, &z);
   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 22 / 22
• Subtask 3: 0 / 29
• Subtask 4: 0 / 42