oj.uz

Submission #369973

# Submission time Handle Problem Language Result Execution time Memory
369973 2021-02-22T20:24:07 Z luciocf Joker (BOI20_joker) C++14
25 / 100
 289 ms 11868 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 = 1; i <= n; 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);

	dsu.init(n);

	opt[0] = 1, opt[m+1] = m;
	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:134:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  134 |   scanf("%d %d", &l, &r);
      |   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Incorrect 1 ms 364 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Incorrect 1 ms 364 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 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 183 ms 10464 KB Output is correct
4 Correct 289 ms 11464 KB Output is correct
5 Correct 160 ms 11820 KB Output is correct
6 Correct 182 ms 10516 KB Output is correct
7 Correct 186 ms 10524 KB Output is correct
8 Correct 227 ms 9692 KB Output is correct
9 Correct 249 ms 9952 KB Output is correct
10 Correct 276 ms 11356 KB Output is correct
11 Correct 224 ms 10460 KB Output is correct
12 Correct 238 ms 11484 KB Output is correct
13 Correct 218 ms 9424 KB Output is correct
14 Correct 225 ms 9948 KB Output is correct
15 Correct 261 ms 10972 KB Output is correct
16 Correct 275 ms 11868 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Incorrect 1 ms 364 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #5
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Incorrect 1 ms 364 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Incorrect 1 ms 364 KB Output isn't correct
5 Halted 0 ms 0 KB -