hdu 4919 ( Exclusive or ) 数论递推

Exclusive or

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)
Total Submission(s): 223    Accepted Submission(s): 84

Problem Description

Given n, find the value of 


Note: ⊕ denotes bitwise exclusive-or.

 

Input

The input consists of several tests. For each tests:

A single integer n (2≤n<10⁵⁰⁰).

 

Output

For each tests:

A single integer, the value of the sum.

 

Sample Input

34

 

Sample Output

64

 

Author

Xiaoxu Guo (ftiasch)

 

Source

2014 Multi-University Training Contest 5

 

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今天学了java 重写了一遍

import java.util.*;import java.math.*;public class Main {    public static void main(String[] args) {        Scanner cin = new Scanner(System.in);        init();        BigInteger N;        while(cin.hasNext())        {            N = cin.nextBigInteger();            System.out.println(get(N));        }        cin.close();    }static Map<BigInteger,BigInteger> map = new HashMap<BigInteger,BigInteger>();        public static void init(){map.put(BigInteger.valueOf(1), BigInteger.valueOf(0));map.put(BigInteger.valueOf(2), BigInteger.valueOf(0));map.put(BigInteger.valueOf(3), BigInteger.valueOf(6));map.put(BigInteger.valueOf(4), BigInteger.valueOf(4));map.put(BigInteger.valueOf(5), BigInteger.valueOf(12));map.put(BigInteger.valueOf(6), BigInteger.valueOf(20));map.put(BigInteger.valueOf(7), BigInteger.valueOf(42));map.put(BigInteger.valueOf(8), BigInteger.valueOf(32));map.put(BigInteger.valueOf(9), BigInteger.valueOf(40));}public static BigInteger get(BigInteger i){BigInteger ret;if(map.containsKey(i)) return map.get(i);else {BigInteger tp= (i.mod(BigInteger.valueOf(2)));if(tp.equals(BigInteger.valueOf(1))){BigInteger ie=i.divide(BigInteger.valueOf(2));ret=(get(ie).multiply(BigInteger.valueOf(4)).add(ie.multiply(BigInteger.valueOf(6))));//get(ie)*4+ie*6;map.put(i, ret);return ret;}else {BigInteger ie=i.divide(BigInteger.valueOf(2));ret=get(ie).add(get(ie.add(BigInteger.valueOf(-1))).add(ie.multiply(BigInteger.valueOf(2))).add(BigInteger.valueOf(-2)));ret=ret.multiply(BigInteger.valueOf(2));map.put(i, ret);return ret;}}}}