package com.klov.essay.youdian;
import java.text.SimpleDateFormat;
import java.util.Date;
public class Essay20140323 {
/**
* 100匹马托100袋粮食,大马每匹驼两袋，小马每匹驼一袋，小马仔2匹驼1袋。求大马、小马、小马子各多少匹
*/
private static void essay1239(){
int answor = 1 ;
for(int babyHorse = 0 ;babyHorse<101;babyHorse=babyHorse+2){
for(int bigHorse = 0;bigHorse<101;bigHorse++){
for(int littleHorse = 0 ;littleHorse<101;littleHorse++){
if((bigHorse+littleHorse+babyHorse==100)&&(bigHorse*2+littleHorse+babyHorse/2==100)){
System.out.println("***answer "+answor+"***********split line**********************");
System.out.println("the bigHorse is : "+bigHorse);
System.out.println("the littleHorse is : "+littleHorse);
System.out.println("the babyHorse is : "+babyHorse);
answor++;
}
}
}
}
}
/**
* 一个数等于所有因数之和则成为完数，如： 6=1+2+3
* 求 10000以内的所有完数
* at 2014-04-05 18:08:17
*****the 1 wanshu : 0******
*****the 2 wanshu : 6******
*****the 3 wanshu : 28******
*****the 4 wanshu : 496******
*/
private static void essay20140405(){
int index = 1 ;
for(int i = 0 ; i < 1001 ; i++){
int sum = 0 ;
for(int j = 1 , max = i/2+1; j < max ; j++ ){
if(i%j==0){
sum+=j ;
}
}
if(i==sum){
System.out.println("*****the "+index+++" wanshu : "+i+"******");
}
}
}
/***********************************
* 计算双数 121、1221
* at 2014-04-05 18:23:50
*/
private static void essay1817(){
int index = 0 ;
for(int i = 10 ; i<100001 ; i++){
if(calculateDoubleData(i)){
System.out.println("*****index "+index+++"***** "+i+"*****");
}
}
}
private static boolean calculateDoubleData(int num){
String numStr = String.valueOf(num) ;
for(int i = 0 ,len = numStr.length()/2 ; i<len ; i++){
if(numStr.charAt(i)!=numStr.charAt(numStr.length()-i-1)){
return false ;
}
}
return true ;
}
/*************************************/
/*************************************
* 求素数：除了1和它本身外没有其他因数的数称为素数
* at 2014-04-05 18:52:38
*/
private static void essay1849(){
int index=1;
for(int i = 3 ; i<30000 ; i++){
if(isPrime(i)){
System.out.println("********the index "+index+++" prime number is "+i+"*****");
}
}
}
private static boolean isPrime(int num){
for(int j = 2 ,max = num/2+1;j<max ; j++ ){
if(num%j==0){
return false ;
}
}
return true ;
}
/*******************************************/
private static void essay1933(){
int[] rabbits = {1,1} ;
for(int i = 3 ; i <=5 ; i=i+2){
rabbits[0] = rabbits[0]+rabbits[1] ;
rabbits[1] = rabbits[0]+rabbits[1] ;
}
System.out.println("******the twentyth month rabbits is "+rabbits[0]);
}
private static void essay1939(){
System.out.println(calculateRabbit(5));
}
private static int calculateRabbit(int month){
if(month==1||month==2){
return 1 ;
}
return calculateRabbit(month-1)+calculateRabbit(month-2) ;
}
private static void calculateRuntime(){
long start = System.currentTimeMillis() ;
essay1933();
System.out.println("*******耗时："+(System.currentTimeMillis()-start));
}
public static void main(String[] args) {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println(format.format(new Date()));
// essay1239();
// essay1939();
essay1849();
// calculateDoubleData(1000);
}
}IT界的一些数学计算题整理,布布扣,bubuko.com
IT界的一些数学计算题整理
原文：http://blog.csdn.net/a_fengzi_code_110/article/details/23000237
