oj.uz

Submission #369978

# Submission time Handle Problem Language Result Execution time Memory
369978 2021-02-22T20:29:53 Z luciocf Joker (BOI20_joker) C++14
25 / 100
 305 ms 8256 KB 
#include <bits/stdc++.h>

#define ff first
#define ss second

using namespace std;

typedef pair<int, int> pii;

const int maxn = 2e5+10;

struct DSU
{
	int pai[maxn], peso[maxn], edge[maxn];
	bool bp;

	struct RollBack
	{
		int u, v, pu;
		bool b;
	};

	stack<RollBack> stk;

	void init(int n)
	{
		bp = 1;
		for (int i = 0; i < maxn; i++)
			pai[i] = i, peso[i] = 1;
	}

	int Find(int x, int &c)
	{
		if (pai[x] == x) return x;

		c ^= edge[x];

		return Find(pai[x], c);
	}

	bool Join(int x, int y)
	{
		int cx = 0, cy = 0;
		x = Find(x, cx), y = Find(y, cy);

		if (peso[x] < peso[y])
		{
			swap(x, y);
			swap(cx, cy);
		}

		stk.push({x, y, peso[x], bp});

		if (x == y) return bp = (bp && (cx != cy));

		pai[y] = x, peso[x] += peso[y];
		edge[y] = cx ^ cy ^ 1;

		return 1;
	}

	void rollback(int x)
	{
		while (stk.size() > x)
		{
			auto E = stk.top(); stk.pop();

			pai[E.u] = E.u, pai[E.v] = E.v;
			peso[E.u] = E.pu, edge[E.v] = 0;
			bp = E.b;
		}
	}
} dsu;

int n, m;

int opt[maxn];
pii edge[maxn];

void solve(int l, int r)
{
	if (l > r) return;

	int mid = (l+r)>>1, s0 = dsu.stk.size();

	for (int i = l; i <= mid; i++)
		dsu.Join(edge[i].ff, edge[i].ss);

	int s1 = dsu.stk.size();

	opt[mid] = mid;

	if (!dsu.bp) opt[mid] = opt[r+1];
	else
	{
		for (int i = opt[r+1]; i >= max(opt[l-1], mid+1); i--)
		{
			if (!dsu.Join(edge[i].ff, edge[i].ss))
			{
				opt[mid] = i;
				break;
			}
		}
	}

	dsu.rollback(s1);
	solve(mid+1, r);

	dsu.rollback(s0);
	for (int i = opt[r+1]; i > opt[mid]; i--)
		dsu.Join(edge[i].ff, edge[i].ss);

	solve(l, mid-1);

	dsu.rollback(s0);
}

int main(void)
{
	int q;
	scanf("%d %d %d", &n, &m, &q);

	for (int i = 1; i <= m; i++)
		scanf("%d %d", &edge[i].ff, &edge[i].ss);
	edge[m+1] = {1, maxn-1};

	dsu.init(n);

	opt[0] = 1, opt[m+1] = m+1;
	solve(1, m);

	while (q--)
	{
		int l, r;
		scanf("%d %d", &l, &r);

		if (opt[l] > r) printf("YES\n");
		else printf("NO\n");
	}
}

Compilation message

Joker.cpp: In member function 'void DSU::rollback(int)':
Joker.cpp:64:21: warning: comparison of integer expressions of different signedness: 'std::stack<DSU::RollBack>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   64 |   while (stk.size() > x)
      |          ~~~~~~~~~~~^~~
Joker.cpp: In function 'int main()':
Joker.cpp:121:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  121 |  scanf("%d %d %d", &n, &m, &q);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:124:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  124 |   scanf("%d %d", &edge[i].ff, &edge[i].ss);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:135:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  135 |   scanf("%d %d", &l, &r);
      |   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 1 ms 1900 KB Output is correct
4 Correct 1 ms 1900 KB Output is correct
5 Incorrect 1 ms 1900 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 1 ms 1900 KB Output is correct
4 Correct 1 ms 1900 KB Output is correct
5 Incorrect 1 ms 1900 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 178 ms 7392 KB Output is correct
4 Correct 305 ms 8256 KB Output is correct
5 Correct 157 ms 7644 KB Output is correct
6 Correct 180 ms 7296 KB Output is correct
7 Correct 182 ms 7276 KB Output is correct
8 Correct 251 ms 7260 KB Output is correct
9 Correct 230 ms 7388 KB Output is correct
10 Correct 267 ms 7772 KB Output is correct
11 Correct 211 ms 7388 KB Output is correct
12 Correct 231 ms 7532 KB Output is correct
13 Correct 252 ms 6892 KB Output is correct
14 Correct 225 ms 7152 KB Output is correct
15 Correct 254 ms 7516 KB Output is correct
16 Correct 270 ms 7644 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 1 ms 1900 KB Output is correct
4 Correct 1 ms 1900 KB Output is correct
5 Incorrect 1 ms 1900 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 1 ms 1900 KB Output is correct
4 Correct 1 ms 1900 KB Output is correct
5 Incorrect 1 ms 1900 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 1 ms 1900 KB Output is correct
4 Correct 1 ms 1900 KB Output is correct
5 Incorrect 1 ms 1900 KB Output isn't correct
6 Halted 0 ms 0 KB -