oj.uz

Submission #369979

# Submission time Handle Problem Language Result Execution time Memory
369979 2021-02-22T20:30:31 Z luciocf Joker (BOI20_joker) C++14
25 / 100
 293 ms 8384 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);

	edge[0] = {1, maxn-1};
	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] = 0, 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:125:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  125 |   scanf("%d %d", &edge[i].ff, &edge[i].ss);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:136:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  136 |   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 2 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 2 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 207 ms 7324 KB Output is correct
4 Correct 277 ms 8384 KB Output is correct
5 Correct 154 ms 7644 KB Output is correct
6 Correct 177 ms 7264 KB Output is correct
7 Correct 200 ms 7436 KB Output is correct
8 Correct 223 ms 7260 KB Output is correct
9 Correct 231 ms 7516 KB Output is correct
10 Correct 279 ms 7772 KB Output is correct
11 Correct 209 ms 7260 KB Output is correct
12 Correct 242 ms 7644 KB Output is correct
13 Correct 219 ms 7296 KB Output is correct
14 Correct 228 ms 7260 KB Output is correct
15 Correct 256 ms 7392 KB Output is correct
16 Correct 293 ms 7660 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 2 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 2 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 2 ms 1900 KB Output is correct
5 Incorrect 1 ms 1900 KB Output isn't correct
6 Halted 0 ms 0 KB -