POJ3349 HASH

给你n个六个数的序列，每一个序列代表一朵雪花，问这n个雪花中存不存相同的雪花，

若存在输出Twin snowflakes found.，否则输出No two snowflakes are alike.

import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import java.io.PrintWriter;import java.math.BigInteger;import java.util.Arrays;import java.util.StringTokenizer;public class Main {public static void main(String args[]) {new Task().solve() ; }}class Task{InputReader in = new InputReader(System.in) ;PrintWriter out = new PrintWriter(System.out) ;final int N = 100008 ;final int Mod = 100007 ;class Node{int[] v ;int next ;Node(){v = new int[6] ;}}Node[] node = new Node[N<<1] ;int[] head = new int[Mod] ;int idx ;void add(int u , int[] v){node[idx] = new Node() ;System.arraycopy(v , 0 , node[idx].v , 0 , 6) ;node[idx].next = head[u] ;head[u] = idx++ ;}boolean find(int u , int[] v){for(int i = head[u] ; i != -1 ; i = node[i].next){Node now = node[i] ;boolean ex = true ;for(int j = 0 ; j < 6 ; j++){if(now.v[j] != v[j]){     ex = false ;     break ; }}if(ex) return true ;}return false ;}void shift(int[] v){int t = v[0] ;for(int i = 0 ; i <= 4 ; i++)v[i] = v[i+1] ;v[5] = t ;}boolean exsit = false ;void doWork(int[] v){int u = 0 ; for(int i = 0 ; i < 6 ; i++){u += v[i] ;}u %= Mod ;for(int i = 0 ; i < 6 ; i++){if(find(u , v)){exsit = true ;return  ;}shift(v) ;}add(u, v) ;for(int i = 0 ; i <= 2 ; i++){int t = v[i] ;v[i] = v[5-i] ;v[5-i] = t ;}add(u , v) ;}void solve(){Arrays.fill(head , -1) ;int n = in.nextInt() ;int[] v = new int[6] ;while(n-- > 0){for(int i = 0 ; i < 6 ; i++){v[i] = in.nextInt() ;}if(! exsit) doWork(v) ;}out.println(exsit ? "Twin snowflakes found." : "No two snowflakes are alike.") ;out.flush() ;}}class InputReader {        public BufferedReader reader;        public StringTokenizer tokenizer;            public InputReader(InputStream stream) {            reader = new BufferedReader(new InputStreamReader(stream), 32768);            tokenizer = new StringTokenizer("");        }            private void eat(String s) {            tokenizer = new StringTokenizer(s);        }            public String nextLine() {            try {                return reader.readLine();            } catch (Exception e) {                return null;            }        }            public boolean hasNext() {            while (!tokenizer.hasMoreTokens()) {                String s = nextLine();                if (s == null)                    return false;                eat(s);            }            return true;        }            public String next() {            hasNext();            return tokenizer.nextToken();        }            public int nextInt() {            return Integer.parseInt(next());        }            public long nextLong() {            return Long.parseLong(next());        }            public double nextDouble() {            return Double.parseDouble(next());        }            public BigInteger nextBigInteger() {            return new BigInteger(next());        }        }