Submission #60678

#	Time	Username	Problem	Language	Result	Execution time	Memory
60678		radoslav11	Ideal city (IOI12_city)	C++14	32 / 100	1076 ms	52588 KiB

city

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

using namespace std;
using namespace __gnu_pbds;
template<class T, class T2> inline int chkmax(T &x, const T2 &y) { return x < y ? x = y, 1 : 0; }
template<class T, class T2> inline int chkmin(T &x, const T2 &y) { return x > y ? x = y, 1 : 0; }
const int MAXN = (1 << 20);
const int mod = (int)1e9;

struct chash { int operator()(pair<int, int> x) const { return x.first * 42 + x.second; } };

int answer;
gp_hash_table<pair<int, int>, int, chash> S;

int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};

int cnt1[MAXN], cnt2[MAXN];
set<int> adj[MAXN];

int par[MAXN], sz[MAXN];
int root(int u) { return u == par[u] ? u : par[u] = root(par[u]); }
int root(pair<int, int> x) { return root(S[x]); }

void unite(pair<int, int> a, pair<int, int> b)
{
	int u = root(S[a]), v = root(S[b]);
	if(u == v) return;
	
	if(sz[u] > sz[v]) 
		swap(u, v);

	sz[v] += sz[u];
	par[u] = v;
}

int dp[MAXN];

void pre_dfs(int u, int pr)
{
	dp[u] = sz[u];
	for(int v: adj[u])
		if(v != pr)
		{
			pre_dfs(v, u);
			dp[u] = (dp[u] + dp[v]) % mod;
		}
}

int n;

void dfs(int u, int pr)
{
	if(u != pr)
	{
		int curr = 0;
		curr = (dp[u] * 1ll * (n - dp[u])) % mod;
		answer = (answer + curr) % mod;
	}

	for(int v: adj[u])
		if(v != pr)
			dfs(v, u);
}

int DistanceSum(int N, int *X, int *Y) 
{
	::n = N;
	answer = 0;
	vector<pair<int, int> > li;
	for(int i = 0; i < N; i++)
		li.push_back({X[i], Y[i]});

	int r, idx = 0;
	for(auto it: li)
		S[it] = ++idx;

	for(int i = 1; i <= idx; i++) adj[i].clear();
	for(int i = 1; i <= idx; i++)
		par[i] = i, sz[i] = 1;

	for(auto it: li)
		for(int d = 0; d < 2; d++)
		{
			pair<int, int> nxt = {dx[d] + it.first, dy[d] + it.second};
			if(S.find(nxt) != S.end())
				unite(nxt, it);
		}

	for(auto it: li)
		for(int d = 2; d < 4; d++)
		{
			pair<int, int> nxt = {dx[d] + it.first, dy[d] + it.second};
			if(S.find(nxt) != S.end())
				adj[root(nxt)].insert(root(S[it]));
		}

	r = root(1);
	pre_dfs(r, r);
	dfs(r, r);

	for(int i = 1; i <= idx; i++) adj[i].clear();
	for(int i = 1; i <= idx; i++)
		par[i] = i, sz[i] = 1;

	for(auto it: li)
		for(int d = 2; d < 4; d++)
		{
			pair<int, int> nxt = {dx[d] + it.first, dy[d] + it.second};
			if(S.find(nxt) != S.end())
				unite(nxt, it);
		}

	for(auto it: li)
		for(int d = 0; d < 2; d++)
		{
			pair<int, int> nxt = {dx[d] + it.first, dy[d] + it.second};
			if(S.find(nxt) != S.end())
				adj[root(nxt)].insert(root(S[it]));
		}

	r = root(1);
	pre_dfs(r, r);
	dfs(r, r);

	return answer;
}

• Subtask 1: 11 / 11
• Subtask 2: 21 / 21
• Subtask 3: 0 / 23
• Subtask 4: 0 / 45