oj.uz

Submission #77477

# Submission time Handle Problem Language Result Execution time Memory
77477 2018-09-28T07:08:08 Z qkxwsm Beads and wires (APIO14_beads) C++17
100 / 100
 257 ms 19984 KB 
/*
    _____
  .'     '.
 /  0   0  \
|     ^     |
|  \     /  |
 \  '---'  /
  '._____.'
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
	int operator()(int x) const
	{
		x ^= (x >> 20) ^ (x >> 12);
		return x ^ (x >> 7) ^ (x >> 4);
	}
};

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using hashtable = gp_hash_table<T, U, chash>;
random_device(rd);
mt19937 rng(rd());

template<class T>
void readi(T &x)
{
	T input = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
	{
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		input = input * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		input = -input;
	}
	x = input;
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int aout[20];
	int ilen = 0;
	while(output)
	{
		aout[ilen] = ((output % 10));
		output /= 10;
		ilen++;
	}
	for (int i = ilen - 1; i >= 0; i--)
	{
		putchar(aout[i] + '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);
}
template<class T, class U>
T 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);
}
template<class T>
T randomize(T mod)
{
	return (uniform_int_distribution<T>(0, mod - 1))(rng);
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#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 200013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;

int N;
vector<pii> edge[MAXN];
int parent[MAXN], dup[MAXN];
vector<int> ord;
int res[2][2];
int dp[MAXN][2][2];
int mx0 = -INF, mx1 = -INF;

void dfs(int u)
{
	for (pii p : edge[u])
	{
		int d = p.fi, v = p.se;
		if (v == parent[u])
		{
			continue;
		}
		parent[v] = u;
		dup[v] = d;
		dfs(v);
	}
	ord.PB(u);
}
void init()
{
	res[0][0] = 0; res[0][1] = 0; res[1][0] = 0; res[1][1] = 0;
	mx0 = -INF; mx1 = -INF;
}
void assign(int u)
{
	ckmax(dp[u][0][0], res[0][0]);
	ckmax(dp[u][0][1], res[0][1]);
	ckmax(dp[u][1][0], res[1][0]);
	ckmax(dp[u][1][1], res[1][1]);
}

int32_t main()
{
	ios_base::sync_with_stdio(0);
	// cout << fixed << setprecision(10);
	// cerr << fixed << setprecision(10);
	// freopen ("file.in", "r", stdin);
	// freopen ("file.out", "w", stdout);
	cin >> N;
	for (int i = 1; i < N; i++)
	{
		int u, v, d;
		cin >> u >> v >> d;
		u--; v--;
		edge[u].PB({d, v});
		edge[v].PB({d, u});
	}
	parent[0] = N; dup[0] = -INF;
	dfs(0);
	for (int i = 0; i < N; i++)
	{
		int u = ord[i];
		// cerr << u << endl;
		//dp[vertex][taking only guy to parent][have u gotten a cut]
		// res[1][0] = dup[u] + sum over all v of dp[v][0][0]
		// res[1][1] = dup[u] + sum over all v of dp[v][0][1]
		for (pii p : edge[u])
		{
			int v = p.se;
			if (v == parent[u]) continue;
			res[0][0] += dp[v][0][0];
			res[0][1] += dp[v][0][0];
			ckmax(mx1, dp[v][0][1] - dp[v][0][0]);
		}
		res[0][1] += mx1;
		res[1][0] = res[0][0] + dup[u];
		res[1][1] = res[0][1] + dup[u];
		assign(u); init();
		//if u dont take u, then:
		//res[0][0] = sum over all v of dp[v][0][0]
		//res[0][1] = sum over all v of dp[v][0][1]
		//if u take two chidlren of u: it's always ok
		//res[0][1] = sum over all v except 2 of dp[v][0][1] plus the two dp[v][1]][1]
		int sum = 0;
		//u choose vertices v1, v2 and v3 and take dp[v1][1][0] + dp[v2][1][1] + dp[rest][0][0]
		for (pii p : edge[u])
		{
			int v = p.se;
			if (v == parent[u]) continue;
			int dif = dp[v][1][0] - dp[v][0][0];
			if (dif > mx0)
			{
				mx1 = mx0; mx0 = dif;
			}
			else if (dif > mx1)
			{
				mx1 = dif;
			}
			sum += dp[v][0][0];
		}
		for (pii p : edge[u])
		{
			int v = p.se;
			if (v == parent[u]) continue;
			ckmax(res[0][1], (dp[v][1][1] - dp[v][0][0]) + ((dp[v][1][0] - dp[v][0][0] == mx0) ? mx1 : mx0) + sum);
		}
		res[1][1] = res[0][1] + dup[u];
		assign(u); init();
		//if u take one child of u and v
		//res[0][0] = sum over all v except 1 of dp[v][0][0] plus dp[v][1][0] + dup[u]
		//res[0][1] = sum over all v except 1 of dp[v][0][0] plus dp[v][1][1] + dup[u]
		res[0][0] = dup[u];
		res[0][1] = dup[u];
		for (pii p : edge[u])
		{
			int v = p.se;
			if (v == parent[u]) continue;
			res[0][0] += dp[v][0][0];
			res[0][1] += dp[v][0][0];
			ckmax(mx0, dp[v][1][0] - dp[v][0][0]);
			ckmax(mx1, dp[v][1][1] - dp[v][0][0]);
		}
		res[0][0] += mx0; res[0][1] += mx1;
		assign(u); init();
		//u just take nothing
		ckmax(dp[u][1][1], dp[u][1][0]);
		ckmax(dp[u][0][1], dp[u][0][0]);
		// cerr << "vertex " << u << ' ' << dp[u][0][0] << ' ' << dp[u][0][1] << ' ' << dp[u][1][0] << ' ' << dp[u][1][1] << endl;
	}
	cout << dp[0][0][1] << '\n';
	//possibilities: u took 1 or u havent
	//ur subtree is stupid or its not
	//the path between anytwo endpoints must go through a third point?
	// cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 4992 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 4992 KB Output is correct
13 Correct 6 ms 5120 KB Output is correct
14 Correct 6 ms 5120 KB Output is correct
15 Correct 6 ms 5092 KB Output is correct
16 Correct 6 ms 4992 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 5120 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 4992 KB Output is correct
13 Correct 6 ms 5120 KB Output is correct
14 Correct 6 ms 5120 KB Output is correct
15 Correct 6 ms 5092 KB Output is correct
16 Correct 6 ms 4992 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 5120 KB Output is correct
23 Correct 8 ms 5376 KB Output is correct
24 Correct 9 ms 5476 KB Output is correct
25 Correct 8 ms 5376 KB Output is correct
26 Correct 11 ms 5760 KB Output is correct
27 Correct 12 ms 5760 KB Output is correct
28 Correct 11 ms 6016 KB Output is correct
29 Correct 10 ms 5760 KB Output is correct
30 Correct 10 ms 5760 KB Output is correct
31 Correct 10 ms 6016 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 4992 KB Output is correct
13 Correct 6 ms 5120 KB Output is correct
14 Correct 6 ms 5120 KB Output is correct
15 Correct 6 ms 5092 KB Output is correct
16 Correct 6 ms 4992 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 5120 KB Output is correct
23 Correct 8 ms 5376 KB Output is correct
24 Correct 9 ms 5476 KB Output is correct
25 Correct 8 ms 5376 KB Output is correct
26 Correct 11 ms 5760 KB Output is correct
27 Correct 12 ms 5760 KB Output is correct
28 Correct 11 ms 6016 KB Output is correct
29 Correct 10 ms 5760 KB Output is correct
30 Correct 10 ms 5760 KB Output is correct
31 Correct 10 ms 6016 KB Output is correct
32 Correct 43 ms 8444 KB Output is correct
33 Correct 41 ms 8448 KB Output is correct
34 Correct 43 ms 8448 KB Output is correct
35 Correct 232 ms 18156 KB Output is correct
36 Correct 234 ms 18156 KB Output is correct
37 Correct 242 ms 18156 KB Output is correct
38 Correct 161 ms 19460 KB Output is correct
39 Correct 156 ms 18492 KB Output is correct
40 Correct 162 ms 18364 KB Output is correct
41 Correct 257 ms 19984 KB Output is correct