oj.uz

Submission #339254

# Submission time Handle Problem Language Result Execution time Memory
339254 2020-12-25T00:46:49 Z KWang31 Mergers (JOI19_mergers) Java 11
100 / 100
 2775 ms 201412 KB 
import java.io.*; import java.util.*;
public class mergers{
  static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } 
  
        String next() 
        { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        
    } 
    
    static int MOD=998244353;
    
    static int[] par,dep;
    static int[] skip;
    public static void main(String[] args){
        FastReader br=new FastReader();
        int N=br.nextInt(); int M=br.nextInt();
        ArrayList<Integer> states[]=new ArrayList[M]; for(int i=0;i<M;i++){states[i]=new ArrayList<>();}
        ArrayList<Integer> adj[]=new ArrayList[N]; for(int i=0;i<N;i++){adj[i]=new ArrayList<>();}
        int a,b;
        for (int i = 0; i < N-1; i++) {
            a=br.nextInt()-1; b=br.nextInt()-1; adj[a].add(b); adj[b].add(a);
        }
        for (int i = 0; i < N; i++) {
            a=br.nextInt()-1; states[a].add(i);
        }
        par=new int[N]; dep=new int[N]; 
        Queue<Integer> qu=new LinkedList<>(); qu.add(0);
        while(!qu.isEmpty()){
            int p=qu.poll();
            for (int i : adj[p]) {
                if(i==par[p])continue;
                par[i]=p; dep[i]=dep[p]+1; qu.add(i);
            }
        }
        
        skip=new int[N];//Skipping: avoiding repeated merging
        for (int i = 0; i < N; i++) {
            skip[i]=i;
        }
        int u;
        for (int i = 0; i < M; i++) {
            if(states[i].isEmpty())continue;
            u=states[i].get(0);
            for (int j = 1; j < states[i].size(); j++) {
                a=u; b=states[i].get(j);
                
                while(a!=b){
                    if(dep[a]>=dep[b]){
                        skip[a]=find(par[a]); a=skip[a]; 
                    }else{
                        skip[b]=find(par[b]); b=skip[b]; 
                    }
                }
                //For each a, we have merged a with its 1st, .., kth ancestor.
                //They belong to the same state
            }
        }
        //In the end, all vertices of the same state have the same skip
        //Therefore, after merging, if two vertices don't have some skip, they are not in the same state
        int[] deg=new int[N];
        
        for (int i = 0; i < N; i++) {
            a=find(i);
            for (int j : adj[i]) {
                if(a!=find(j)){
                    //Notice in the compressed form, there is only one leader for each state, namely j
                    //If i is adjacent to two vertices with same find, i must have that find too
                    deg[a]++;
                }
            }
        }
        //System.out.println(Arrays.toString(deg));
        int ans=0;
        for (int i = 0; i < N; i++) {
            if(deg[i]==1)ans++;
        }
        System.out.println((ans+1)/2);
        //If a state is a leaf, there exist exactly one 
    }
    
    public static int find(int x){
        if(skip[x]==x)return x;
        skip[x]=find(skip[x]); return skip[x];
    }
    /*
    public static void dfs(ArrayList<Integer>[] adj, int p, int v){
        for (int c : adj[v]) {
            if(c==p)continue;
            dep[c]=dep[v]+1; par[c]=v; dfs(adj,v,c);
        }
    }*/
}
//Debugging:
//Are you sure your algorithm is correct?
//Bounds: long
//Special cases: n=0,1?
//Make sure you remove your debugging code before you submit!

Compilation message

Note: mergers.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 8428 KB Output is correct
2 Correct 76 ms 8556 KB Output is correct
3 Correct 76 ms 8556 KB Output is correct
4 Correct 73 ms 8448 KB Output is correct
5 Correct 73 ms 8556 KB Output is correct
6 Correct 79 ms 8556 KB Output is correct
7 Correct 73 ms 8664 KB Output is correct
8 Correct 79 ms 8556 KB Output is correct
9 Correct 71 ms 8588 KB Output is correct
10 Correct 73 ms 8556 KB Output is correct
11 Correct 77 ms 8536 KB Output is correct
12 Correct 75 ms 8556 KB Output is correct
13 Correct 74 ms 8428 KB Output is correct
14 Correct 77 ms 8560 KB Output is correct
15 Correct 79 ms 8556 KB Output is correct
16 Correct 72 ms 8428 KB Output is correct
17 Correct 72 ms 8556 KB Output is correct
18 Correct 77 ms 8596 KB Output is correct
19 Correct 72 ms 8540 KB Output is correct
20 Correct 71 ms 8556 KB Output is correct
21 Correct 76 ms 8556 KB Output is correct
22 Correct 76 ms 8684 KB Output is correct
23 Correct 71 ms 8556 KB Output is correct
24 Correct 73 ms 8556 KB Output is correct

Subtask #2
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 8428 KB Output is correct
2 Correct 76 ms 8556 KB Output is correct
3 Correct 76 ms 8556 KB Output is correct
4 Correct 73 ms 8448 KB Output is correct
5 Correct 73 ms 8556 KB Output is correct
6 Correct 79 ms 8556 KB Output is correct
7 Correct 73 ms 8664 KB Output is correct
8 Correct 79 ms 8556 KB Output is correct
9 Correct 71 ms 8588 KB Output is correct
10 Correct 73 ms 8556 KB Output is correct
11 Correct 77 ms 8536 KB Output is correct
12 Correct 75 ms 8556 KB Output is correct
13 Correct 74 ms 8428 KB Output is correct
14 Correct 77 ms 8560 KB Output is correct
15 Correct 79 ms 8556 KB Output is correct
16 Correct 72 ms 8428 KB Output is correct
17 Correct 72 ms 8556 KB Output is correct
18 Correct 77 ms 8596 KB Output is correct
19 Correct 72 ms 8540 KB Output is correct
20 Correct 71 ms 8556 KB Output is correct
21 Correct 76 ms 8556 KB Output is correct
22 Correct 76 ms 8684 KB Output is correct
23 Correct 71 ms 8556 KB Output is correct
24 Correct 73 ms 8556 KB Output is correct
25 Correct 75 ms 8540 KB Output is correct
26 Correct 300 ms 14672 KB Output is correct
27 Correct 293 ms 14432 KB Output is correct
28 Correct 304 ms 14688 KB Output is correct
29 Correct 302 ms 14688 KB Output is correct
30 Correct 290 ms 14304 KB Output is correct
31 Correct 73 ms 8556 KB Output is correct
32 Correct 305 ms 14904 KB Output is correct
33 Correct 76 ms 8684 KB Output is correct
34 Correct 298 ms 14696 KB Output is correct
35 Correct 296 ms 14800 KB Output is correct
36 Correct 294 ms 14480 KB Output is correct
37 Correct 295 ms 14688 KB Output is correct
38 Correct 82 ms 8684 KB Output is correct
39 Correct 328 ms 14884 KB Output is correct
40 Correct 342 ms 14440 KB Output is correct
41 Correct 320 ms 14548 KB Output is correct
42 Correct 296 ms 14644 KB Output is correct
43 Correct 290 ms 14560 KB Output is correct
44 Correct 77 ms 8556 KB Output is correct
45 Correct 348 ms 14776 KB Output is correct
46 Correct 349 ms 14816 KB Output is correct
47 Correct 82 ms 8704 KB Output is correct
48 Correct 293 ms 14688 KB Output is correct
49 Correct 298 ms 14816 KB Output is correct
50 Correct 296 ms 14688 KB Output is correct
51 Correct 298 ms 14552 KB Output is correct
52 Correct 295 ms 14560 KB Output is correct
53 Correct 293 ms 14740 KB Output is correct
54 Correct 294 ms 14688 KB Output is correct

Subtask #3
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 8428 KB Output is correct
2 Correct 76 ms 8556 KB Output is correct
3 Correct 76 ms 8556 KB Output is correct
4 Correct 73 ms 8448 KB Output is correct
5 Correct 73 ms 8556 KB Output is correct
6 Correct 79 ms 8556 KB Output is correct
7 Correct 73 ms 8664 KB Output is correct
8 Correct 79 ms 8556 KB Output is correct
9 Correct 71 ms 8588 KB Output is correct
10 Correct 73 ms 8556 KB Output is correct
11 Correct 77 ms 8536 KB Output is correct
12 Correct 75 ms 8556 KB Output is correct
13 Correct 74 ms 8428 KB Output is correct
14 Correct 77 ms 8560 KB Output is correct
15 Correct 79 ms 8556 KB Output is correct
16 Correct 72 ms 8428 KB Output is correct
17 Correct 72 ms 8556 KB Output is correct
18 Correct 77 ms 8596 KB Output is correct
19 Correct 72 ms 8540 KB Output is correct
20 Correct 71 ms 8556 KB Output is correct
21 Correct 76 ms 8556 KB Output is correct
22 Correct 76 ms 8684 KB Output is correct
23 Correct 71 ms 8556 KB Output is correct
24 Correct 73 ms 8556 KB Output is correct
25 Correct 75 ms 8556 KB Output is correct
26 Correct 808 ms 40560 KB Output is correct
27 Correct 752 ms 35764 KB Output is correct
28 Correct 292 ms 14560 KB Output is correct
29 Correct 75 ms 8556 KB Output is correct
30 Correct 74 ms 8808 KB Output is correct
31 Correct 766 ms 35684 KB Output is correct
32 Correct 291 ms 14684 KB Output is correct
33 Correct 806 ms 37604 KB Output is correct
34 Correct 803 ms 35576 KB Output is correct
35 Correct 318 ms 14600 KB Output is correct
36 Correct 810 ms 35812 KB Output is correct
37 Correct 342 ms 14432 KB Output is correct
38 Correct 296 ms 14580 KB Output is correct
39 Correct 768 ms 39720 KB Output is correct
40 Correct 293 ms 14796 KB Output is correct
41 Correct 729 ms 35556 KB Output is correct
42 Correct 788 ms 36808 KB Output is correct
43 Correct 76 ms 8684 KB Output is correct
44 Correct 800 ms 36744 KB Output is correct
45 Correct 788 ms 36836 KB Output is correct
46 Correct 297 ms 14816 KB Output is correct
47 Correct 302 ms 14560 KB Output is correct

Subtask #4
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 766 ms 36804 KB Output is correct
2 Correct 822 ms 44132 KB Output is correct
3 Correct 299 ms 14576 KB Output is correct
4 Correct 293 ms 14432 KB Output is correct
5 Correct 75 ms 8556 KB Output is correct
6 Correct 76 ms 8556 KB Output is correct
7 Correct 295 ms 14680 KB Output is correct
8 Correct 805 ms 38508 KB Output is correct
9 Correct 293 ms 14560 KB Output is correct
10 Correct 765 ms 35412 KB Output is correct
11 Correct 78 ms 8556 KB Output is correct
12 Correct 769 ms 35452 KB Output is correct
13 Correct 802 ms 38456 KB Output is correct
14 Correct 879 ms 46992 KB Output is correct
15 Correct 762 ms 39632 KB Output is correct
16 Correct 299 ms 14688 KB Output is correct
17 Correct 75 ms 8556 KB Output is correct
18 Correct 824 ms 47900 KB Output is correct
19 Correct 840 ms 46768 KB Output is correct
20 Correct 345 ms 14800 KB Output is correct
21 Correct 79 ms 8556 KB Output is correct
22 Correct 858 ms 43512 KB Output is correct
23 Correct 299 ms 14628 KB Output is correct
24 Correct 766 ms 35940 KB Output is correct
25 Correct 832 ms 46480 KB Output is correct
26 Correct 297 ms 14760 KB Output is correct
27 Correct 293 ms 14688 KB Output is correct
28 Correct 294 ms 14756 KB Output is correct
29 Correct 293 ms 14560 KB Output is correct
30 Correct 297 ms 14560 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 8428 KB Output is correct
2 Correct 76 ms 8556 KB Output is correct
3 Correct 76 ms 8556 KB Output is correct
4 Correct 73 ms 8448 KB Output is correct
5 Correct 73 ms 8556 KB Output is correct
6 Correct 79 ms 8556 KB Output is correct
7 Correct 73 ms 8664 KB Output is correct
8 Correct 79 ms 8556 KB Output is correct
9 Correct 71 ms 8588 KB Output is correct
10 Correct 73 ms 8556 KB Output is correct
11 Correct 77 ms 8536 KB Output is correct
12 Correct 75 ms 8556 KB Output is correct
13 Correct 74 ms 8428 KB Output is correct
14 Correct 77 ms 8560 KB Output is correct
15 Correct 79 ms 8556 KB Output is correct
16 Correct 72 ms 8428 KB Output is correct
17 Correct 72 ms 8556 KB Output is correct
18 Correct 77 ms 8596 KB Output is correct
19 Correct 72 ms 8540 KB Output is correct
20 Correct 71 ms 8556 KB Output is correct
21 Correct 76 ms 8556 KB Output is correct
22 Correct 76 ms 8684 KB Output is correct
23 Correct 71 ms 8556 KB Output is correct
24 Correct 73 ms 8556 KB Output is correct
25 Correct 75 ms 8540 KB Output is correct
26 Correct 300 ms 14672 KB Output is correct
27 Correct 293 ms 14432 KB Output is correct
28 Correct 304 ms 14688 KB Output is correct
29 Correct 302 ms 14688 KB Output is correct
30 Correct 290 ms 14304 KB Output is correct
31 Correct 73 ms 8556 KB Output is correct
32 Correct 305 ms 14904 KB Output is correct
33 Correct 76 ms 8684 KB Output is correct
34 Correct 298 ms 14696 KB Output is correct
35 Correct 296 ms 14800 KB Output is correct
36 Correct 294 ms 14480 KB Output is correct
37 Correct 295 ms 14688 KB Output is correct
38 Correct 82 ms 8684 KB Output is correct
39 Correct 328 ms 14884 KB Output is correct
40 Correct 342 ms 14440 KB Output is correct
41 Correct 320 ms 14548 KB Output is correct
42 Correct 296 ms 14644 KB Output is correct
43 Correct 290 ms 14560 KB Output is correct
44 Correct 77 ms 8556 KB Output is correct
45 Correct 348 ms 14776 KB Output is correct
46 Correct 349 ms 14816 KB Output is correct
47 Correct 82 ms 8704 KB Output is correct
48 Correct 293 ms 14688 KB Output is correct
49 Correct 298 ms 14816 KB Output is correct
50 Correct 296 ms 14688 KB Output is correct
51 Correct 298 ms 14552 KB Output is correct
52 Correct 295 ms 14560 KB Output is correct
53 Correct 293 ms 14740 KB Output is correct
54 Correct 294 ms 14688 KB Output is correct
55 Correct 75 ms 8556 KB Output is correct
56 Correct 808 ms 40560 KB Output is correct
57 Correct 752 ms 35764 KB Output is correct
58 Correct 292 ms 14560 KB Output is correct
59 Correct 75 ms 8556 KB Output is correct
60 Correct 74 ms 8808 KB Output is correct
61 Correct 766 ms 35684 KB Output is correct
62 Correct 291 ms 14684 KB Output is correct
63 Correct 806 ms 37604 KB Output is correct
64 Correct 803 ms 35576 KB Output is correct
65 Correct 318 ms 14600 KB Output is correct
66 Correct 810 ms 35812 KB Output is correct
67 Correct 342 ms 14432 KB Output is correct
68 Correct 296 ms 14580 KB Output is correct
69 Correct 768 ms 39720 KB Output is correct
70 Correct 293 ms 14796 KB Output is correct
71 Correct 729 ms 35556 KB Output is correct
72 Correct 788 ms 36808 KB Output is correct
73 Correct 76 ms 8684 KB Output is correct
74 Correct 800 ms 36744 KB Output is correct
75 Correct 788 ms 36836 KB Output is correct
76 Correct 297 ms 14816 KB Output is correct
77 Correct 302 ms 14560 KB Output is correct
78 Correct 766 ms 36804 KB Output is correct
79 Correct 822 ms 44132 KB Output is correct
80 Correct 299 ms 14576 KB Output is correct
81 Correct 293 ms 14432 KB Output is correct
82 Correct 75 ms 8556 KB Output is correct
83 Correct 76 ms 8556 KB Output is correct
84 Correct 295 ms 14680 KB Output is correct
85 Correct 805 ms 38508 KB Output is correct
86 Correct 293 ms 14560 KB Output is correct
87 Correct 765 ms 35412 KB Output is correct
88 Correct 78 ms 8556 KB Output is correct
89 Correct 769 ms 35452 KB Output is correct
90 Correct 802 ms 38456 KB Output is correct
91 Correct 879 ms 46992 KB Output is correct
92 Correct 762 ms 39632 KB Output is correct
93 Correct 299 ms 14688 KB Output is correct
94 Correct 75 ms 8556 KB Output is correct
95 Correct 824 ms 47900 KB Output is correct
96 Correct 840 ms 46768 KB Output is correct
97 Correct 345 ms 14800 KB Output is correct
98 Correct 79 ms 8556 KB Output is correct
99 Correct 858 ms 43512 KB Output is correct
100 Correct 299 ms 14628 KB Output is correct
101 Correct 766 ms 35940 KB Output is correct
102 Correct 832 ms 46480 KB Output is correct
103 Correct 297 ms 14760 KB Output is correct
104 Correct 293 ms 14688 KB Output is correct
105 Correct 294 ms 14756 KB Output is correct
106 Correct 293 ms 14560 KB Output is correct
107 Correct 297 ms 14560 KB Output is correct
108 Correct 2100 ms 143228 KB Output is correct
109 Correct 2135 ms 130964 KB Output is correct
110 Correct 2244 ms 126572 KB Output is correct
111 Correct 2757 ms 192572 KB Output is correct
112 Correct 2707 ms 184928 KB Output is correct
113 Correct 2428 ms 195096 KB Output is correct
114 Correct 2307 ms 129640 KB Output is correct
115 Correct 2224 ms 129416 KB Output is correct
116 Correct 2492 ms 140852 KB Output is correct
117 Correct 2725 ms 201104 KB Output is correct
118 Correct 2402 ms 127060 KB Output is correct
119 Correct 2775 ms 201000 KB Output is correct
120 Correct 2612 ms 181172 KB Output is correct
121 Correct 2649 ms 201412 KB Output is correct
122 Correct 2641 ms 171272 KB Output is correct
123 Correct 2158 ms 183520 KB Output is correct
124 Correct 2646 ms 191228 KB Output is correct