从5随机到7随机及其扩展

Love The Way You Lie 2022-05-28 01:05 151阅读 0赞

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//从5随机到7随机及其扩展
    public class RandomInt{
    	
        public static int rand1To5()
        {
        	 return (int)(Math.random()*5)+1;
        }
        
        //产生1-7的随机函数
        public static int rand1To7()
        {
        	  //return rand1To5()+2;
        	int num=0;
        	do{
        		num=(rand1To5()-1)*5+rand1To5()-1;
        	}while(num>20);
        	return num%7+1;
        }
    //*************************************************************
        public static int rand01p()
        {
        	  //可随意改变p
        	 double p=0.83;
        	 return Math.random()<p?0:1;
        }
        public static int rand01()
        {
        	 int num=0;
        	 do{
               num=rand01p();
        	 }while(num==rand01p());
        	 return num;
        }
        public static int rand0To3()
        {
        	 return rand01()*2+rand01();
        }
        //产生1-6的随机函数
        public static int rand1To6()
        {  
        	int num=0;
        	do{
        		 num=rand0To3()*4+rand0To3();
    
        	}while(num>11);
        	
        	return num%6+1;
        	
        }
     //************************************************************
        public static int rand1ToM(int m)
        {
        	return (int)(Math.random()*m)+1;
        }
        //产生1-n的随机函数
    	public static int rand1ToN(int n, int m) {
    		int[] nMSys = getMSysNum(n - 1, m);
    		int[] randNum = getRanMSysNumLessN(nMSys, m);
    		return getNumFromMSysNum(randNum, m) + 1;
    	}
    
    	// 把value转成m进制的数
    	public static int[] getMSysNum(int value, int m) {
    		int[] res = new int[32];
    		int index = res.length - 1;
    		while (value != 0) {
    			res[index--] = value % m;
    			value = value / m;
    		}
    		return res;
    	}
    
    	// 等概率随机产生一个0~nMsys范围上的数，只不过是m进制表达的。
    	public static int[] getRanMSysNumLessN(int[] nMSys, int m) {
    		int[] res = new int[nMSys.length];
    		int start = 0;
    		while (nMSys[start] == 0) {
    			start++;
    		}
    		int index = start;
    		boolean lastEqual = true;
    		while (index != nMSys.length) {
    			res[index] = rand1ToM(m) - 1;
    			if (lastEqual) {
    				if (res[index] > nMSys[index]) {
    					index = start;
    					lastEqual = true;
    					continue;
    				} else {
    					lastEqual = res[index] == nMSys[index];
    				}
    			}
    			index++;
    		}
    		return res;
    	}
    
    	// 把m进制的数转成10进制
    	public static int getNumFromMSysNum(int[] mSysNum, int m) {
    		int res = 0;
    		for (int i = 0; i != mSysNum.length; i++) {
    			res = res * m + mSysNum[i];
    		}
    		return res;
    	}
    //**************************************************************
    	public static void main(String[]args)
    	{
    		System.out.println(rand1To7());
            System.out.println(rand1To6());
            System.out.println(rand1ToN(4,5));
    	}
    }

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[Center]: /images/20220528/9bfd177cb473493ebd339244d9e62e7c.png
[Center 1]: /images/20220528/b42a2f3180f8407d845a86a8fe40d120.png