剑指Offer32 丑数

 /*************************************************************************

     > File Name: 32_UglyNumber.c

     > Author: Juntaran

     > Mail: [email protected]

     > Created Time: 2016年09月02日 星期五 12时29分59秒

  ************************************************************************/

 #include <stdio.h>

 #include <malloc.h>

 int isUgly(int number)

 {

     while (number %  == )

         number /= ;

     while (number %  == )

         number /= ;

     while (number %  == )

         number /= ;

     return (number==) ?  : -;

 }

 // 低效方法

 int getUglyNumber1(int n)

 {

     if (n <= )

         return -;

     int number = ;

     while (n != )

     {

         ++ number;

         if (isUgly(number) == )

             n --;

     }

     printf("%d\n", number);

     return number;

 }

 int MinOfThree(int a, int b, int c)

 {

     int minNum = a>b ? b : a;

     minNum = minNum>c ? c : minNum;

     return minNum;

 }

 // 高效方法 空间换时间

 int getUglyNumber2(int index)

 {

     if (index <= )

         return index;

     int* ugly = (int*)malloc(sizeof(int) * index);

     int i2 = ;

     int i3 = ;

     int i5 = ;

     ugly[] = ;

     for (int i = ; i < index; ++i)

     {

         int temp2 = ugly[i2] * ;

         int temp3 = ugly[i3] * ;

         int temp5 = ugly[i5] * ;

         int minNum = MinOfThree(temp2, temp3, temp5);

         ugly[i] = minNum;

         if (minNum == temp2)

             i2 ++;

         if (minNum == temp3)

             i3 ++;

         if (minNum == temp5)

             i5 ++;

     }

     printf("%d\n", ugly[index - ]);

     return ugly[index - ];

 }

 int main()

 {

     getUglyNumber1();

     getUglyNumber2();

 }