Submission #569185

#	Time	Username	Problem	Language	Result	Execution time	Memory
569185		aryan12	Street Lamps (APIO19_street_lamps)	C++17	20 / 100	1587 ms	159752 KiB

street_lamps

#include <bits/stdc++.h>
using namespace std;
#define int long long

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

const int N = 5e5 + 5;
int DP[21][N * 2];

struct node
{
	int max_par, value, depth;
} *reach_tree[N * 2];

int Find(int x)
{
	if(x == reach_tree[x]->max_par)
	{
		return x;
	}
	return reach_tree[x]->max_par = Find(reach_tree[x]->max_par);
}

void Unite(int a, int b, int x, int val)
{
	a = Find(a), b = Find(b);
	// cout << "Uniting: " << a << ", " << b << ", to: (" << x << ", " << val << ")\n";
	DP[0][a] = x;
	DP[0][b] = x;
	reach_tree[a]->max_par = x;
	reach_tree[b]->max_par = x;
	reach_tree[x]->value = val;
}

int LCA(int x, int y, int omk)
{
	int ok_x = x, ok_y = y;
	int depth_x = 1, depth_y = 1;
	for(int i = 20; i >= 0; i--)
	{
		if(DP[i][ok_x] != omk)
		{
			ok_x = DP[i][ok_x];
			depth_x += (1 << i);
		}
		if(DP[i][ok_y] != omk)
		{
			ok_y = DP[i][ok_y];
			depth_y += (1 << i);
		}
	}
	if(depth_x > depth_y)
	{
		swap(x, y);
		swap(depth_x, depth_y);
	}
	int diff = depth_y - depth_x;
	for(int i = 20; i >= 0; i--)
	{
		if((1 << i) & diff)
		{
			y = DP[i][y];
		}
	}
	if(x == y) return x;
	for(int i = 20; i >= 0; i--)
	{
		if(DP[i][x] != DP[i][y])
		{
			x = DP[i][x];
			y = DP[i][y];
		}
	}
	return DP[0][x];
}

void Solve() 
{
	int n, q;
	cin >> n >> q;
	for(int i = 0; i < N * 2; i++)
	{
		reach_tree[i] = new node();
		DP[0][i] = i;
		reach_tree[i]->max_par = i;
		reach_tree[i]->value = 0;
	}
	// vector<array<int, 2> > a(n + 1, {0, -1}); // alr occurred, start pos (start pos = -1 if off)
	string s;
	cin >> s;
	int next_one = n + 1;
	for(int i = 0; i < n; i++) 
	{
		if(s[i] == '1')
		{
			// cout << "i = " << i << ", i + 1 = " << i + 1 << "\n";
			Unite(i, i + 1, next_one++, 0LL);
		}
	}
	vector<array<int, 3> > queries;
	for(int i = 1; i <= q; i++)
	{
		string command;
		cin >> command;
		if(command == "query")
		{
			int a, b;
			cin >> a >> b;
			a--, b--;
			queries.push_back({a, b, i});
		}
		else
		{
			int idx;
			cin >> idx;
			idx--;
			Unite(idx, idx + 1, next_one++, i);
		}
	}
	for(int i = 1; i < 21; i++)
	{
		for(int j = 0; j < next_one; j++)
		{
			DP[i][j] = DP[i - 1][DP[i - 1][j]];
		}
	}
	// for(int i = 0; i < 20; i++)
	// {
	// 	for(int j = 0; j < next_one; j++)
	// 	{
	// 		cout << DP[i][j] << " ";
	// 	}
	// 	cout << "\n";
	// }
	for(int i = 0; i < queries.size(); i++)
	{
		if(Find(queries[i][0]) != Find(queries[i][1]))
		{
			cout << "0\n";
			continue;
		}
		int lca = LCA(queries[i][0], queries[i][1], next_one - 1);
		// cout << "lca = " << lca << "\n";
		cout << max(0LL, queries[i][2] - reach_tree[lca]->value) << "\n";
	}
}

int32_t main() 
{
	auto begin = std::chrono::high_resolution_clock::now();
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t = 1;
	// cin >> t;
	for(int i = 1; i <= t; i++) 
	{
		//cout << "Case #" << i << ": ";
		Solve();
	}
	auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
	return 0;
}

Compilation message (stderr)

street_lamps.cpp: In function 'void Solve()':
street_lamps.cpp:135:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::array<long long int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  135 |  for(int i = 0; i < queries.size(); i++)
      |                 ~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20