oj.uz

Submission #299549

# Submission time Handle Problem Language Result Execution time Memory
299549 2020-09-15T07:20:43 Z E869120 Joker (BOI20_joker) C++14
25 / 100
 447 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 << 30)) 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 11 ms 12672 KB Output is correct
2 Correct 9 ms 12672 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Runtime error 26 ms 25472 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12672 KB Output is correct
2 Correct 9 ms 12672 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Runtime error 26 ms 25472 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12672 KB Output is correct
2 Correct 9 ms 12672 KB Output is correct
3 Correct 181 ms 25336 KB Output is correct
4 Correct 219 ms 27256 KB Output is correct
5 Correct 273 ms 24952 KB Output is correct
6 Correct 173 ms 21544 KB Output is correct
7 Correct 177 ms 21112 KB Output is correct
8 Correct 165 ms 19576 KB Output is correct
9 Correct 193 ms 21532 KB Output is correct
10 Correct 305 ms 24784 KB Output is correct
11 Correct 181 ms 21364 KB Output is correct
12 Correct 245 ms 24560 KB Output is correct
13 Correct 129 ms 17400 KB Output is correct
14 Correct 151 ms 19448 KB Output is correct
15 Correct 240 ms 22832 KB Output is correct
16 Correct 447 ms 24760 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12672 KB Output is correct
2 Correct 9 ms 12672 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Runtime error 26 ms 25472 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -

Subtask #5
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12672 KB Output is correct
2 Correct 9 ms 12672 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Runtime error 26 ms 25472 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 12672 KB Output is correct
2 Correct 9 ms 12672 KB Output is correct
3 Correct 9 ms 12672 KB Output is correct
4 Runtime error 26 ms 25472 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -