oj.uz

Submission #369981

# Submission time Handle Problem Language Result Execution time Memory
369981 2021-02-22T20:32:47 Z luciocf Joker (BOI20_joker) C++14
25 / 100
 294 ms 8880 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] = {0, 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 2 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 Incorrect 1 ms 1900 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

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

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 1900 KB Output is correct
2 Correct 1 ms 1900 KB Output is correct
3 Correct 187 ms 7312 KB Output is correct
4 Correct 272 ms 8880 KB Output is correct
5 Correct 156 ms 7648 KB Output is correct
6 Correct 217 ms 7264 KB Output is correct
7 Correct 184 ms 7264 KB Output is correct
8 Correct 221 ms 7264 KB Output is correct
9 Correct 236 ms 7392 KB Output is correct
10 Correct 274 ms 7792 KB Output is correct
11 Correct 224 ms 7336 KB Output is correct
12 Correct 251 ms 7532 KB Output is correct
13 Correct 220 ms 6892 KB Output is correct
14 Correct 223 ms 7264 KB Output is correct
15 Correct 282 ms 7392 KB Output is correct
16 Correct 294 ms 7648 KB Output is correct

Subtask #4
0 / 10.0

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

Subtask #5
0 / 22.0

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

Subtask #6
0 / 29.0

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