oj.uz

Submission #1703

# Submission time Handle Problem Language Result Execution time Memory
1703 2013-07-12T15:52:41 Z model_code Parachute rings (IOI12_rings) C++
100 / 100
 2001 ms 85800 KB 
/*
	O(N+M+C) solution for Rings (N = number of vertices; M = number of calls to Link; C = number of calls to CountCritical).
	
	Author: Giovanni Paolini
*/

#include <cstdio>
#include <vector>
#include <cassert>


using namespace std;

int const MAXN = 1000000;

int n;
bool quadruplication = 0;

int numcycles = 0;
int cycle_length; // If numcycles==1, here we store the length of the only cycle

int other_endpoint[4][MAXN]; // -1 if the node is not an endpoint, otherwise the other endpoint
vector<int> neighbours[MAXN];

int destroyed[4]; // The destroyed node of each graph (only if quadruplication==TRUE)
int degree[4][MAXN];
bool islinear[4]; // Whether each graph is linear or not

void Init(int k) {
	n = k;
	
	for (int i=0; i<n; ++i) {
		other_endpoint[0][i] = i;
	}
}

void add_new_edge(int x, int y) {
	// Adds an edge in case of quadruplication
	
	for (int i=0; i<4; ++i) {
		
		// Operating on graph i
		
		if ( !islinear[i] ) continue;
		if ( x == destroyed[i] || y == destroyed[i] ) continue;
		
		degree[i][x]++;
		degree[i][y]++;
		
		assert( degree[i][x] <= 3 && degree[i][y] <= 3 );
		
		if ( degree[i][x] == 3 || degree[i][y] == 3 ) {
			islinear[i] = 0;
			continue;
		}
		
		if ( other_endpoint[i][x] == y ) {
			// Cycle!
			
			islinear[i] = 0;
			continue;
		}
		
		
		
		int a = other_endpoint[i][x];
		int b = other_endpoint[i][y];
		
		other_endpoint[i][x] = -1;
		other_endpoint[i][y] = -1;
		other_endpoint[i][a] = b;
		other_endpoint[i][b] = a;
		
	}
	
}


void quadruplicate (int x) {
	
	quadruplication = 1;
	
	destroyed[0] = x;
	destroyed[1] = neighbours[x][0];
	destroyed[2] = neighbours[x][1];
	destroyed[3] = neighbours[x][2];
	
	for (int i=0; i<4; ++i) {
		for (int j=0; j<n; ++j) {
			other_endpoint[i][j] = j;
			degree[i][j] = 0;
		}
	}
	
	for (int i=0; i<4; ++i) {
		islinear[i] = 1;
	}
	
	for (int k=0; k<n; ++k) {
		for (vector<int>::iterator j = neighbours[k].begin(); j != neighbours[k].end(); ++j) {
			
			if ( k < (*j) )	add_new_edge( k, (*j) );
			
		}
	}
	
}

void Link(int xx, int yy) {
	
	int x = xx;
	int y = yy;
	
	if ( quadruplication == 0 ) {
		
		neighbours[x].push_back(y);
		neighbours[y].push_back(x);
		
		degree[0][x]++;
		degree[0][y]++;
		
		// If a node has degree 3, only it or its neighbours can be critical. So we can keep track of each of the 4 graphs obtained by removing one of these 4 nodes.
		if ( degree[0][x] == 3 ) {
			quadruplicate(x);
			return;
		}
		if ( degree[0][y] == 3 ) {
			quadruplicate(y);
			return;
		}
		
		// If their degree is < 3, then they were necessarily endpoints!
		
		if ( other_endpoint[0][x] != y ) { // A longer path is formed
			int a = other_endpoint[0][x];
			int b = other_endpoint[0][y];
			
			other_endpoint[0][x] = -1;
			other_endpoint[0][y] = -1;
			other_endpoint[0][a] = b;
			other_endpoint[0][b] = a;
		}
		else {	// A cycle is formed
			numcycles++;
			if ( numcycles == 1 ) {
				
				int length = 1;
				int previous_node = x;
				int current_node = neighbours[x][0];
				
				while ( current_node != x ) {
					int possibility = neighbours[ current_node ][0];
					if ( possibility == previous_node ) possibility = neighbours[ current_node ][1];
					
					previous_node = current_node;
					current_node = possibility;
					
					length++;
				}
				
				cycle_length = length;
				
			}
		}
	}
	
	else {
		
		add_new_edge(x,y);
		
	}
}

int CountCritical() {
	
	if ( quadruplication == 0 ) {
		
		switch (numcycles) {
			case 0:
				return n;
			
			case 1:
				return cycle_length;
			
			default:
				return 0;
		}
		
	}
	else {
		
		int answer = 0;
		for (int i=0; i<4; ++i) {
			if ( islinear[i] ) answer++;
		}
		return answer;
		
	}
	
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 24 ms 24052 KB Output is correct
3 Correct 23 ms 24216 KB Output is correct
4 Correct 27 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 25 ms 24216 KB Output is correct
7 Correct 23 ms 24224 KB Output is correct
8 Correct 23 ms 24224 KB Output is correct
9 Correct 26 ms 24444 KB Output is correct
10 Correct 25 ms 24444 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 473 ms 44428 KB Output is correct
2 Correct 795 ms 63100 KB Output is correct
3 Correct 351 ms 63100 KB Output is correct
4 Correct 1372 ms 63100 KB Output is correct
5 Correct 1467 ms 63376 KB Output is correct
6 Correct 1403 ms 63376 KB Output is correct
7 Correct 349 ms 63376 KB Output is correct
8 Correct 1560 ms 79868 KB Output is correct
9 Correct 2001 ms 85800 KB Output is correct
10 Correct 859 ms 85800 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 24 ms 24052 KB Output is correct
3 Correct 23 ms 24216 KB Output is correct
4 Correct 27 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 25 ms 24216 KB Output is correct
7 Correct 23 ms 24224 KB Output is correct
8 Correct 23 ms 24224 KB Output is correct
9 Correct 26 ms 24444 KB Output is correct
10 Correct 25 ms 24444 KB Output is correct
11 Correct 23 ms 85800 KB Output is correct
12 Correct 27 ms 85800 KB Output is correct
13 Correct 25 ms 85800 KB Output is correct
14 Correct 24 ms 85800 KB Output is correct
15 Correct 24 ms 85800 KB Output is correct
16 Correct 26 ms 85800 KB Output is correct
17 Correct 25 ms 85800 KB Output is correct
18 Correct 26 ms 85800 KB Output is correct
19 Correct 26 ms 85800 KB Output is correct
20 Correct 27 ms 85800 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 24 ms 24052 KB Output is correct
3 Correct 23 ms 24216 KB Output is correct
4 Correct 27 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 25 ms 24216 KB Output is correct
7 Correct 23 ms 24224 KB Output is correct
8 Correct 23 ms 24224 KB Output is correct
9 Correct 26 ms 24444 KB Output is correct
10 Correct 25 ms 24444 KB Output is correct
11 Correct 23 ms 85800 KB Output is correct
12 Correct 27 ms 85800 KB Output is correct
13 Correct 25 ms 85800 KB Output is correct
14 Correct 24 ms 85800 KB Output is correct
15 Correct 24 ms 85800 KB Output is correct
16 Correct 26 ms 85800 KB Output is correct
17 Correct 25 ms 85800 KB Output is correct
18 Correct 26 ms 85800 KB Output is correct
19 Correct 26 ms 85800 KB Output is correct
20 Correct 27 ms 85800 KB Output is correct
21 Correct 42 ms 85800 KB Output is correct
22 Correct 57 ms 85800 KB Output is correct
23 Correct 66 ms 85800 KB Output is correct
24 Correct 55 ms 85800 KB Output is correct
25 Correct 36 ms 85800 KB Output is correct
26 Correct 52 ms 85800 KB Output is correct
27 Correct 76 ms 85800 KB Output is correct
28 Correct 53 ms 85800 KB Output is correct
29 Correct 52 ms 85800 KB Output is correct
30 Correct 85 ms 85800 KB Output is correct

Subtask #5
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 23800 KB Output is correct
2 Correct 24 ms 24052 KB Output is correct
3 Correct 23 ms 24216 KB Output is correct
4 Correct 27 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 25 ms 24216 KB Output is correct
7 Correct 23 ms 24224 KB Output is correct
8 Correct 23 ms 24224 KB Output is correct
9 Correct 26 ms 24444 KB Output is correct
10 Correct 25 ms 24444 KB Output is correct
11 Correct 473 ms 44428 KB Output is correct
12 Correct 795 ms 63100 KB Output is correct
13 Correct 351 ms 63100 KB Output is correct
14 Correct 1372 ms 63100 KB Output is correct
15 Correct 1467 ms 63376 KB Output is correct
16 Correct 1403 ms 63376 KB Output is correct
17 Correct 349 ms 63376 KB Output is correct
18 Correct 1560 ms 79868 KB Output is correct
19 Correct 2001 ms 85800 KB Output is correct
20 Correct 859 ms 85800 KB Output is correct
21 Correct 23 ms 85800 KB Output is correct
22 Correct 27 ms 85800 KB Output is correct
23 Correct 25 ms 85800 KB Output is correct
24 Correct 24 ms 85800 KB Output is correct
25 Correct 24 ms 85800 KB Output is correct
26 Correct 26 ms 85800 KB Output is correct
27 Correct 25 ms 85800 KB Output is correct
28 Correct 26 ms 85800 KB Output is correct
29 Correct 26 ms 85800 KB Output is correct
30 Correct 27 ms 85800 KB Output is correct
31 Correct 42 ms 85800 KB Output is correct
32 Correct 57 ms 85800 KB Output is correct
33 Correct 66 ms 85800 KB Output is correct
34 Correct 55 ms 85800 KB Output is correct
35 Correct 36 ms 85800 KB Output is correct
36 Correct 52 ms 85800 KB Output is correct
37 Correct 76 ms 85800 KB Output is correct
38 Correct 53 ms 85800 KB Output is correct
39 Correct 52 ms 85800 KB Output is correct
40 Correct 85 ms 85800 KB Output is correct
41 Correct 260 ms 85800 KB Output is correct
42 Correct 775 ms 85800 KB Output is correct
43 Correct 263 ms 85800 KB Output is correct
44 Correct 328 ms 85800 KB Output is correct
45 Correct 484 ms 85800 KB Output is correct
46 Correct 785 ms 85800 KB Output is correct
47 Correct 1132 ms 85800 KB Output is correct
48 Correct 323 ms 85800 KB Output is correct
49 Correct 793 ms 85800 KB Output is correct
50 Correct 874 ms 85800 KB Output is correct
51 Correct 273 ms 85800 KB Output is correct
52 Correct 350 ms 85800 KB Output is correct
53 Correct 283 ms 85800 KB Output is correct
54 Correct 1276 ms 85800 KB Output is correct
55 Correct 541 ms 85800 KB Output is correct