oj.uz

Submission #15609

# Submission time Handle Problem Language Result Execution time Memory
15609 2015-07-13T10:18:26 Z gs14004 Parachute rings (IOI12_rings) C++14
100 / 100
 1912 ms 85884 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 23 ms 24052 KB Output is correct
3 Correct 22 ms 24216 KB Output is correct
4 Correct 21 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 23 ms 24216 KB Output is correct
7 Correct 22 ms 24240 KB Output is correct
8 Correct 23 ms 24240 KB Output is correct
9 Correct 24 ms 24372 KB Output is correct
10 Correct 24 ms 24372 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 485 ms 44484 KB Output is correct
2 Correct 832 ms 63152 KB Output is correct
3 Correct 355 ms 63152 KB Output is correct
4 Correct 1254 ms 63268 KB Output is correct
5 Correct 1255 ms 63268 KB Output is correct
6 Correct 1464 ms 63268 KB Output is correct
7 Correct 363 ms 63268 KB Output is correct
8 Correct 1563 ms 79868 KB Output is correct
9 Correct 1912 ms 85884 KB Output is correct
10 Correct 848 ms 85884 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 23 ms 24052 KB Output is correct
3 Correct 22 ms 24216 KB Output is correct
4 Correct 21 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 23 ms 24216 KB Output is correct
7 Correct 22 ms 24240 KB Output is correct
8 Correct 23 ms 24240 KB Output is correct
9 Correct 24 ms 24372 KB Output is correct
10 Correct 24 ms 24372 KB Output is correct
11 Correct 59 ms 85884 KB Output is correct
12 Correct 28 ms 85884 KB Output is correct
13 Correct 27 ms 85884 KB Output is correct
14 Correct 31 ms 85884 KB Output is correct
15 Correct 32 ms 85884 KB Output is correct
16 Correct 35 ms 85884 KB Output is correct
17 Correct 25 ms 85884 KB Output is correct
18 Correct 26 ms 85884 KB Output is correct
19 Correct 28 ms 85884 KB Output is correct
20 Correct 26 ms 85884 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 23 ms 24052 KB Output is correct
3 Correct 22 ms 24216 KB Output is correct
4 Correct 21 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 23 ms 24216 KB Output is correct
7 Correct 22 ms 24240 KB Output is correct
8 Correct 23 ms 24240 KB Output is correct
9 Correct 24 ms 24372 KB Output is correct
10 Correct 24 ms 24372 KB Output is correct
11 Correct 59 ms 85884 KB Output is correct
12 Correct 28 ms 85884 KB Output is correct
13 Correct 27 ms 85884 KB Output is correct
14 Correct 31 ms 85884 KB Output is correct
15 Correct 32 ms 85884 KB Output is correct
16 Correct 35 ms 85884 KB Output is correct
17 Correct 25 ms 85884 KB Output is correct
18 Correct 26 ms 85884 KB Output is correct
19 Correct 28 ms 85884 KB Output is correct
20 Correct 26 ms 85884 KB Output is correct
21 Correct 28 ms 85884 KB Output is correct
22 Correct 56 ms 85884 KB Output is correct
23 Correct 72 ms 85884 KB Output is correct
24 Correct 52 ms 85884 KB Output is correct
25 Correct 38 ms 85884 KB Output is correct
26 Correct 53 ms 85884 KB Output is correct
27 Correct 78 ms 85884 KB Output is correct
28 Correct 53 ms 85884 KB Output is correct
29 Correct 50 ms 85884 KB Output is correct
30 Correct 92 ms 85884 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 23 ms 24052 KB Output is correct
3 Correct 22 ms 24216 KB Output is correct
4 Correct 21 ms 24216 KB Output is correct
5 Correct 22 ms 24216 KB Output is correct
6 Correct 23 ms 24216 KB Output is correct
7 Correct 22 ms 24240 KB Output is correct
8 Correct 23 ms 24240 KB Output is correct
9 Correct 24 ms 24372 KB Output is correct
10 Correct 24 ms 24372 KB Output is correct
11 Correct 485 ms 44484 KB Output is correct
12 Correct 832 ms 63152 KB Output is correct
13 Correct 355 ms 63152 KB Output is correct
14 Correct 1254 ms 63268 KB Output is correct
15 Correct 1255 ms 63268 KB Output is correct
16 Correct 1464 ms 63268 KB Output is correct
17 Correct 363 ms 63268 KB Output is correct
18 Correct 1563 ms 79868 KB Output is correct
19 Correct 1912 ms 85884 KB Output is correct
20 Correct 848 ms 85884 KB Output is correct
21 Correct 59 ms 85884 KB Output is correct
22 Correct 28 ms 85884 KB Output is correct
23 Correct 27 ms 85884 KB Output is correct
24 Correct 31 ms 85884 KB Output is correct
25 Correct 32 ms 85884 KB Output is correct
26 Correct 35 ms 85884 KB Output is correct
27 Correct 25 ms 85884 KB Output is correct
28 Correct 26 ms 85884 KB Output is correct
29 Correct 28 ms 85884 KB Output is correct
30 Correct 26 ms 85884 KB Output is correct
31 Correct 28 ms 85884 KB Output is correct
32 Correct 56 ms 85884 KB Output is correct
33 Correct 72 ms 85884 KB Output is correct
34 Correct 52 ms 85884 KB Output is correct
35 Correct 38 ms 85884 KB Output is correct
36 Correct 53 ms 85884 KB Output is correct
37 Correct 78 ms 85884 KB Output is correct
38 Correct 53 ms 85884 KB Output is correct
39 Correct 50 ms 85884 KB Output is correct
40 Correct 92 ms 85884 KB Output is correct
41 Correct 259 ms 85884 KB Output is correct
42 Correct 796 ms 85884 KB Output is correct
43 Correct 265 ms 85884 KB Output is correct
44 Correct 357 ms 85884 KB Output is correct
45 Correct 505 ms 85884 KB Output is correct
46 Correct 803 ms 85884 KB Output is correct
47 Correct 1209 ms 85884 KB Output is correct
48 Correct 315 ms 85884 KB Output is correct
49 Correct 821 ms 85884 KB Output is correct
50 Correct 869 ms 85884 KB Output is correct
51 Correct 255 ms 85884 KB Output is correct
52 Correct 338 ms 85884 KB Output is correct
53 Correct 279 ms 85884 KB Output is correct
54 Correct 1263 ms 85884 KB Output is correct
55 Correct 485 ms 85884 KB Output is correct