Submission #505997

#	Time	Username	Problem	Language	Result	Execution time	Memory
505997		mansur	Hard route (IZhO17_road)	C++17	0 / 100	7 ms	12064 KiB

road

#include<bits/stdc++.h>	
 
#pragma optimize ("g",on)
#pragma GCC optimize ("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("03")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
#pragma comment(linker, "/stack:200000000")

//01001101 01100001 01101011 01101000 01100001  01100111 01100001 01111001 

using namespace std;

#define all(a) a.begin(), a.end()                                                   
#define rall(a) a.rbegin(), a.rend()
#define ll long long
#define pb push_back
#define sz(a) a.size()
#define nl '\n'
#define popb pop_back()                                                                   
#define ld double
#define ull unsigned long long
#define ff first                                         
#define ss second  
#define fix fixed << setprecision
#define pii pair<int, int>                          
#define E exit (0)
#define int long long
 
const int inf = 1e9, N = 5e5 + 1, mod = 998244353;                    

vector<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

vector<int> adj[N];

map<int, int> cn;

multiset<int> s;

int d[N], d2[N];

int mx, cc;

void dfs(int u, int p, int cur = -1) {
	d[u] = d[p] + 1;
	for (auto e: adj[u]) {
		if (e != p) {
			dfs(e, u, (cur == -1 ? e : cur));
			d2[u] = max(d2[u], d2[e] + 1);
		}
	}
}

void calc(int u, int p) {
	multiset<int> cur;
	map<int, int> c;
	int x = d[u] + (s.empty() ? -1 : *--s.end());
	cur.insert(inf - x);
	int y = 1;
	if (!s.empty()) y = cn[*--s.end()];
	c[x] += y;
	for (auto e: adj[u]) {
		if (e != p) {
			calc(e, u);
			cur.insert(inf - d2[e] - 1);
			c[d2[e] + 1]++;
		}
	}
	for (auto e: adj[u]) {
		if (e == p) continue;
		cur.erase(cur.find(inf - d2[e] - 1));
		c[d2[e] + 1]--;
		int sum = 0, cnt = 0;
		vector<int> h;
		for (auto e: cur) {
			sum += inf - e;
			h.pb(inf - e);
			cnt++;
			if (cnt == 2) break;
		}
		if (cnt == 2) {
			int val = (d2[e] + 1) * sum;
			if (val > mx) mx = val, cc = 0;
			if (val == mx) {
				if (h[0] == h[1]) cc += c[h[0]] * (c[h[0]] - 1) / 2;
				else cc += c[h[0]] * c[h[1]];
			}
		}
		c[d2[e] + 1]++;
		cur.insert(inf - d2[e] - 1);
	}
	cur.erase(cur.find(inf - x));
	c[x] -= y;
	int sum = 0, cnt = 0;
	vector<int> h;
	for (auto e: cur) {
		sum += inf - e;
		cnt++;
		h.pb(inf - e);
		if (cnt == 2) break;
	}
	if (cnt == 2) {
		int val = x * sum;
		if (val > mx) mx = val, cc = 0;
		if (val == mx) {
			if (h[0] == h[1]) cc += c[h[0]] * (c[h[0]] - 1) / 2;
			else cc += c[h[0]] * c[h[1]];
		}
	}
	if (sz(adj[u]) == 1) {
		if (mx == 0) cc += y;
	}
}

main() {                                                         
	//freopen("cowrect.in", "r", stdin);                                                                                     
	//freopen("cowrect.out", "w", stdout);                                                                                     
	ios_base::sync_with_stdio(NULL);                                                                                        
	cin.tie(NULL);
	int n;
	cin >> n;
	for (int i = 1; i < n; i++) {
		int u, v;
		cin >> u >> v;
		adj[u].pb(v);
		adj[v].pb(u);	
   	}
   	dfs(1, 1);
   	for (auto e: adj[1]) {
   		s.insert(d2[e]);
   		cn[d2[e]]++;
   	}
   	for (auto e: adj[1]) {
   		s.erase(s.find(d2[e]));
		cn[d2[e]]--;
   		calc(e, 1);
   		s.insert(d2[e]);
		cn[d2[e]]++;
   	}
   	cout << mx << ' ' << cc;
}

Compilation message (stderr)

road.cpp:3: warning: ignoring '#pragma optimize ' [-Wunknown-pragmas]
    3 | #pragma optimize ("g",on)
      | 
road.cpp:9: warning: ignoring '#pragma comment ' [-Wunknown-pragmas]
    9 | #pragma comment(linker, "/stack:200000000")
      | 
road.cpp:116:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  116 | main() {
      | ^~~~

• Subtask 1: 0 / 19
• Subtask 2: 0 / 33
• Subtask 3: 0 / 48