oj.uz

Submission #299550

# Submission time Handle Problem Language Result Execution time Memory
299550 2020-09-15T07:21:27 Z E869120 Joker (BOI20_joker) C++14
25 / 100
 322 ms 27256 KB 
#include <bits/stdc++.h>
using namespace std;

class UnionFind {
	public:
	vector<int> par;
	
	void init(int sz) {
		par.resize(sz, -1);
	}
	int root(int pos) {
		if (par[pos] == -1) return pos;
		par[pos] = root(par[pos]);
		return par[pos];
	}
	void unite(int u, int v) {
		u = root(u);
		v = root(v);
		if (u == v) return;
		par[u] = v;
	}
	bool same(int u, int v) {
		if (root(u) == root(v)) return true;
		return false;
	}
};

// Input
int N;
int M, A[1 << 18], B[1 << 18];
int Q, L[1 << 18], R[1 << 18];

// Graph
vector<int> X[1 << 18];
int col[1 << 18];
bool flag;

// Subtask3
vector<pair<int, int>> Y[1 << 18];
int lim[1 << 18];
bool used[1 << 18];
bool reached[1 << 18];

void henhari(int idx) {
	for (int i = 1; i <= N; i++) Y[i].clear();
	for (int i = 1; i <= idx; i++) {
		if (used[i] == false) continue;
		Y[A[i]].push_back(make_pair(B[i], 1000000000));
		Y[B[i]].push_back(make_pair(A[i], 1000000000));
	}
	for (int i = idx + 1; i <= M; i++) {
		if (used[i] == false) continue;
		Y[A[i]].push_back(make_pair(B[i], i));
		Y[B[i]].push_back(make_pair(A[i], i));
	}
}

void dfs2(int pos, int dep) {
	col[pos] = dep;
	for (pair<int, int> i : Y[pos]) {
		if (col[i.first] >= 0) continue;
		dfs2(i.first, dep ^ 1);
	}
}

void coloring() {
	for (int i = 1; i <= N; i++) col[i] = -1;
	for (int i = 1; i <= N; i++) {
		if (col[i] >= 0) continue;
		dfs2(i, 0);
	}
}

int dfs3(int pos, int to) {
	if (pos == to) return (1 << 30);
	reached[pos] = true;
	int ret = 0;
	for (pair<int, int> i : Y[pos]) {
		if (reached[i.first] == true) continue;
		int z = dfs3(i.first, to);
		ret = max(ret, min(z, i.second));
	}
	return ret;
}

int getedge(int a, int b) {
	for (int i = 1; i <= N; i++) reached[i] = false;
	int x = dfs3(a, b);
	return x;
}

void solve_subtask3() {
	int maxL = 0;
	for (int i = 1; i <= Q; i++) maxL = max(maxL, L[i]);
	
	// Step #1. Maeshori
	UnionFind UF;
	UF.init(N + 2);
	for (int i = M; i >= 1; i--) {
		if (UF.same(A[i], B[i]) == true) continue;
		UF.unite(A[i], B[i]);
		used[i] = true;
	}
	
	// Step #2. Maeshori 2
	henhari(0);
	coloring();
	
	// Step #3. Get Answer
	for (int i = 1; i <= maxL; i++) {
		for (int j = i; j <= M; j++) {
			if (used[j] == false && col[A[j]] == col[B[j]]) lim[i] = j;
		}
		int v = getedge(A[i], B[i]);
		if (v >= (1 << 27)) continue;
		used[v] = false;
		used[i] = true;
		henhari(i);
		coloring();
	}
	
	// Step #4. Output
	for (int i = 1; i <= Q; i++) {
		if (lim[L[i]] > R[i]) printf("YES\n");
		else printf("NO\n");
	}
}

void dfs(int pos, int dep) {
	col[pos] = dep;
	for (int i : X[pos]) {
		if (col[i] != -1) {
			if (col[i] == dep) flag = true;
			continue;
		}
		dfs(i, dep ^ 1);
	}
}

bool solve(int l, int r) {
	flag = false;
	for (int i = 1; i <= N; i++) X[i].clear();
	for (int i = 1; i <= M; i++) {
		if (l <= i && i <= r) continue;
		X[A[i]].push_back(B[i]);
		X[B[i]].push_back(A[i]);
	}
	for (int i = 1; i <= N; i++) col[i] = -1;
	for (int i = 1; i <= N; i++) {
		if (col[i] >= 0) continue;
		dfs(i, 0);
	}
	return flag;
}

void solve_subtask1() {
	for (int i = 1; i <= Q; i++) {
		bool ans = solve(L[i], R[i]);
		if (ans == false) printf("NO\n");
		else printf("YES\n");
	}
}

int main() {
	scanf("%d%d%d", &N, &M, &Q);
	for (int i = 1; i <= M; i++) scanf("%d%d", &A[i], &B[i]);
	for (int i = 1; i <= Q; i++) scanf("%d%d", &L[i], &R[i]);
	
	if (N <= 0 && M <= 2000 && Q <= 2000) solve_subtask1();
	else solve_subtask3();
	return 0;
}

Compilation message

Joker.cpp: In function 'int main()':
Joker.cpp:165:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  165 |  scanf("%d%d%d", &N, &M, &Q);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:166:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  166 |  for (int i = 1; i <= M; i++) scanf("%d%d", &A[i], &B[i]);
      |                               ~~~~~^~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:167:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  167 |  for (int i = 1; i <= Q; i++) scanf("%d%d", &L[i], &R[i]);
      |                               ~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 12672 KB Output is correct
2 Correct 9 ms 12800 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Incorrect 9 ms 12672 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 12672 KB Output is correct
2 Correct 9 ms 12800 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Incorrect 9 ms 12672 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 9 ms 12672 KB Output is correct
2 Correct 9 ms 12800 KB Output is correct
3 Correct 158 ms 25208 KB Output is correct
4 Correct 222 ms 27256 KB Output is correct
5 Correct 274 ms 24952 KB Output is correct
6 Correct 159 ms 21496 KB Output is correct
7 Correct 167 ms 21116 KB Output is correct
8 Correct 152 ms 19576 KB Output is correct
9 Correct 196 ms 21368 KB Output is correct
10 Correct 308 ms 24824 KB Output is correct
11 Correct 186 ms 21492 KB Output is correct
12 Correct 252 ms 24688 KB Output is correct
13 Correct 127 ms 17528 KB Output is correct
14 Correct 150 ms 19448 KB Output is correct
15 Correct 264 ms 23040 KB Output is correct
16 Correct 322 ms 24696 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 12672 KB Output is correct
2 Correct 9 ms 12800 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Incorrect 9 ms 12672 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #5
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 12672 KB Output is correct
2 Correct 9 ms 12800 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Incorrect 9 ms 12672 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 12672 KB Output is correct
2 Correct 9 ms 12800 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Incorrect 9 ms 12672 KB Output isn't correct
5 Halted 0 ms 0 KB -