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Submission #39072

# Submission time Handle Problem Language Result Execution time Memory
39072 2018-01-09T07:10:12 Z Aidyn_A Hard route (IZhO17_road) C++14
19 / 100
 2000 ms 100728 KB 
#include <stdio.h>
#include <bits/stdc++.h>			

#define pb push_back
#define pf push_front
#define pp pop_back
#define sz(a) (int)(a.size())
#define mp make_pair
#define F first
#define S second
#define next _next
#define prev _prev
#define left _left
#define right _right
#define y1 _y1
#define all(x) x.begin(), x.end()
#define what_is(x) #x << " is " << (x)

using namespace std;

typedef long long ll;

const int N = 5005;
const int inf = (int)1e9;

int n;
vector<int> g[N];
int down[N], u[N];
int up[15][N], tin[N], tout[N], timer;
int dist[N];
int ver[N];

void dfs(int x, int pr = 0) {
	tin[x] = ++ timer;
	ver[timer] = x;
	up[0][x] = pr;
	for(int i = 1; i <= 13; i ++)
		up[i][x] = up[i - 1][up[i - 1][x]];		
	for(auto to : g[x]) {
		if(to == pr)
			continue;
		dist[to] = dist[x] + 1;
		dfs(to, x);
		down[x] = max(down[x], down[to] + 1);	
	}
	tout[x] = timer;
}

bool is_par(int x, int y) {
	return (tin[x] <= tin[y] && tout[x] >= tout[y]);
}

int lca(int x, int y) {
	if(is_par(x, y)) return x;
	if(is_par(y, x)) return y;
	int v = x;
	for(int i = 13; i >= 0; i --) 
		if(up[i][v] > 0 && !is_par(up[i][v], y))
			v = up[i][v];
  return up[0][v]; 	
}

void calc_u(int x, int pr = 0) {
	int mx1 = -inf, mx2 = -inf;
	for(auto to : g[x]) {
		if(to == pr)
			continue;
		if(down[to] > mx1)
			mx2 = mx1, mx1 = down[to];			
		else 
			mx2 = max(mx2, down[to]);
	}
	for(auto to : g[x]) {
		if(to == pr) 
			continue;
		u[to] = max(u[to], u[x] + 1);
		if(mx1 == down[to])
			u[to] = max(u[to], mx2 + 2);
		else
			u[to] = max(u[to], mx1 + 2);
	}
	for(auto to : g[x]) {
		if(to == pr)
			continue;
		calc_u(to, x);
	}
}

short bar[5005][5005], rab[5005][5005];
int pos[5005];
vector<int> leaf;

void calc_bar() {
	for(int i = 0; i < sz(leaf); i ++) 
		for(int j = i + 1; j < sz(leaf); j ++) 
			bar[i][j] = max(bar[i][j - 1], short(dist[leaf[j]] - dist[lca(leaf[i], leaf[j])]));
	for(int i = 0; i < sz(leaf); i ++) 
		for(int j = i - 1; j >= 0; j --) 
			rab[j][i] = max(rab[j + 1][i], short(dist[leaf[j]] - dist[lca(leaf[i], leaf[j])]));
}

main() {
	//freopen("road.in", "r", stdin);
	//freopen("road.out", "w", stdout);
	cin >> n;
	for(int i = 1, x, y; i < n; i ++) {
		cin >> x >> y;	
		g[x].pb(y), g[y].pb(x);
	}
	if(n == 2) {
		cout << "0 1";
		return 0;		
	}
	int start = 1;
	for(int i = 1; i <= n; i ++) {
		if(sz(g[i]) != 1) {
			start = i;
			break;
		}
	}
	dfs(start);
	calc_u(start);
	//cout << "start: " << start << "\n";

	for(int i = 1; i <= n; i ++) {
		//cout << "i: " << i << " up: " << u[i] << "\n";
		int x = ver[i];
		pos[i] = sz(leaf);
		if(sz(g[x]) == 1) 
			leaf.pb(x);		
	}
	calc_bar();
	ll mx = 0;
	int mx_cnt = 0;
	for(int i = 0; i < sz(leaf); i ++) {
		int prv = -1, cur = 0, temp = 0, what = 0;
		for(int j = i + 1; j < sz(leaf); j ++) {
			int _lca = lca(leaf[i], leaf[j]), tempo = 0;	
 			cur = max(cur, (int)rab[pos[tin[_lca]]][i]);
 			
 			tempo = bar[j][max(j, pos[tout[_lca]])];
			if(prv == _lca) 
				what = max(what, dist[leaf[j - 1]] - dist[lca(leaf[j - 1], leaf[j])]);
			if(prv != -1 && prv != _lca)
				cur = max(cur, temp), what = 0;
			ll val = 1ll * max({tempo, cur, u[_lca], what}) * (dist[leaf[i]] + dist[leaf[j]] - 2 * dist[_lca]);
			//cout << leaf[i] << ' ' << leaf[j] << " cur: " << max({cur, u[_lca], tempo, what})  << " lca: " << _lca << " tin: " << tin[_lca] << " pos: " << pos[tin[_lca]] << " rab: " << rab[pos[tin[_lca]]][i] << "\n"; 
			if(val == mx)
				mx_cnt ++;
			if(val > mx)
				mx = val, mx_cnt = 1;
			prv = _lca;
			temp = max(temp, dist[leaf[j]] - dist[_lca]);
		}                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
	}
	cout << mx << ' ' << mx_cnt;
	return 0;         
}

Compilation message

road.cpp:102:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

Subtask #1
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 100416 KB Output is correct
2 Correct 0 ms 100416 KB Output is correct
3 Correct 0 ms 100416 KB Output is correct
4 Correct 0 ms 100416 KB Output is correct
5 Correct 0 ms 100416 KB Output is correct
6 Correct 0 ms 100416 KB Output is correct
7 Correct 0 ms 100416 KB Output is correct
8 Correct 0 ms 100416 KB Output is correct
9 Correct 0 ms 100416 KB Output is correct
10 Correct 0 ms 100416 KB Output is correct
11 Correct 0 ms 100416 KB Output is correct
12 Correct 0 ms 100416 KB Output is correct
13 Correct 0 ms 100416 KB Output is correct
14 Correct 0 ms 100416 KB Output is correct
15 Correct 0 ms 100416 KB Output is correct
16 Correct 0 ms 100416 KB Output is correct
17 Correct 0 ms 100416 KB Output is correct
18 Correct 0 ms 100416 KB Output is correct
19 Correct 0 ms 100416 KB Output is correct
20 Correct 0 ms 100416 KB Output is correct
21 Correct 0 ms 100416 KB Output is correct
22 Correct 0 ms 100416 KB Output is correct
23 Correct 0 ms 100416 KB Output is correct
24 Correct 0 ms 100416 KB Output is correct

Subtask #2
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 100416 KB Output is correct
2 Correct 0 ms 100416 KB Output is correct
3 Correct 0 ms 100416 KB Output is correct
4 Correct 0 ms 100416 KB Output is correct
5 Correct 0 ms 100416 KB Output is correct
6 Correct 0 ms 100416 KB Output is correct
7 Correct 0 ms 100416 KB Output is correct
8 Correct 0 ms 100416 KB Output is correct
9 Correct 0 ms 100416 KB Output is correct
10 Correct 0 ms 100416 KB Output is correct
11 Correct 0 ms 100416 KB Output is correct
12 Correct 0 ms 100416 KB Output is correct
13 Correct 0 ms 100416 KB Output is correct
14 Correct 0 ms 100416 KB Output is correct
15 Correct 0 ms 100416 KB Output is correct
16 Correct 0 ms 100416 KB Output is correct
17 Correct 0 ms 100416 KB Output is correct
18 Correct 0 ms 100416 KB Output is correct
19 Correct 0 ms 100416 KB Output is correct
20 Correct 0 ms 100416 KB Output is correct
21 Correct 0 ms 100416 KB Output is correct
22 Correct 0 ms 100416 KB Output is correct
23 Correct 0 ms 100416 KB Output is correct
24 Correct 0 ms 100416 KB Output is correct
25 Correct 283 ms 100548 KB Output is correct
26 Correct 249 ms 100560 KB Output is correct
27 Correct 326 ms 100548 KB Output is correct
28 Correct 173 ms 100584 KB Output is correct
29 Correct 1256 ms 100680 KB Output is correct
30 Correct 826 ms 100692 KB Output is correct
31 Correct 853 ms 100692 KB Output is correct
32 Correct 963 ms 100680 KB Output is correct
33 Correct 3 ms 100556 KB Output is correct
34 Correct 6 ms 100588 KB Output is correct
35 Correct 3 ms 100580 KB Output is correct
36 Correct 3 ms 100560 KB Output is correct
37 Correct 3 ms 100608 KB Output is correct
38 Correct 6 ms 100728 KB Output is correct
39 Correct 3 ms 100548 KB Output is correct
40 Correct 3 ms 100548 KB Output is correct
41 Correct 3 ms 100548 KB Output is correct
42 Correct 9 ms 100548 KB Output is correct
43 Correct 6 ms 100548 KB Output is correct
44 Correct 9 ms 100548 KB Output is correct
45 Correct 33 ms 100548 KB Output is correct
46 Correct 113 ms 100548 KB Output is correct
47 Correct 589 ms 100692 KB Output is correct
48 Execution timed out 2000 ms 100680 KB Execution timed out

Subtask #3
0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 100416 KB Output is correct
2 Correct 0 ms 100416 KB Output is correct
3 Correct 0 ms 100416 KB Output is correct
4 Correct 0 ms 100416 KB Output is correct
5 Correct 0 ms 100416 KB Output is correct
6 Correct 0 ms 100416 KB Output is correct
7 Correct 0 ms 100416 KB Output is correct
8 Correct 0 ms 100416 KB Output is correct
9 Correct 0 ms 100416 KB Output is correct
10 Correct 0 ms 100416 KB Output is correct
11 Correct 0 ms 100416 KB Output is correct
12 Correct 0 ms 100416 KB Output is correct
13 Correct 0 ms 100416 KB Output is correct
14 Correct 0 ms 100416 KB Output is correct
15 Correct 0 ms 100416 KB Output is correct
16 Correct 0 ms 100416 KB Output is correct
17 Correct 0 ms 100416 KB Output is correct
18 Correct 0 ms 100416 KB Output is correct
19 Correct 0 ms 100416 KB Output is correct
20 Correct 0 ms 100416 KB Output is correct
21 Correct 0 ms 100416 KB Output is correct
22 Correct 0 ms 100416 KB Output is correct
23 Correct 0 ms 100416 KB Output is correct
24 Correct 0 ms 100416 KB Output is correct
25 Correct 283 ms 100548 KB Output is correct
26 Correct 249 ms 100560 KB Output is correct
27 Correct 326 ms 100548 KB Output is correct
28 Correct 173 ms 100584 KB Output is correct
29 Correct 1256 ms 100680 KB Output is correct
30 Correct 826 ms 100692 KB Output is correct
31 Correct 853 ms 100692 KB Output is correct
32 Correct 963 ms 100680 KB Output is correct
33 Correct 3 ms 100556 KB Output is correct
34 Correct 6 ms 100588 KB Output is correct
35 Correct 3 ms 100580 KB Output is correct
36 Correct 3 ms 100560 KB Output is correct
37 Correct 3 ms 100608 KB Output is correct
38 Correct 6 ms 100728 KB Output is correct
39 Correct 3 ms 100548 KB Output is correct
40 Correct 3 ms 100548 KB Output is correct
41 Correct 3 ms 100548 KB Output is correct
42 Correct 9 ms 100548 KB Output is correct
43 Correct 6 ms 100548 KB Output is correct
44 Correct 9 ms 100548 KB Output is correct
45 Correct 33 ms 100548 KB Output is correct
46 Correct 113 ms 100548 KB Output is correct
47 Correct 589 ms 100692 KB Output is correct
48 Execution timed out 2000 ms 100680 KB Execution timed out