剑指Offer06 旋转数组的最小值

 /*************************************************************************
     > File Name: 06_MinNumberInRotatedArray.c
     > Author: Juntaran
     > Mail: JuntaranMail@gmail.com
     > Created Time: 2016年08月29日 星期一 20时14分22秒
  ************************************************************************/

 #include <stdio.h>
 #include <stdlib.h>

 // O(n)解法
 int minNumberInRotatedArray1(int* rotatedArray, int length)
 {
     if (length <= )
         return ;

     for (int i = ; i < length; ++i)
     {
         if ( rotatedArray[i] < rotatedArray[i-])
             return rotatedArray[i];
     }
     return rotatedArray[];
 }

 // O(log(n))解法
 int minNumberInRotatedArray2(int* rotatedArray, int length)
 {
     if (length <= )
         return ;
     if (length == )
         return rotatedArray[];
     int left  = ;
     int right = length - ;
     int middle = ;

     if (rotatedArray[left] < rotatedArray[right])
         return rotatedArray[];

     while (rotatedArray[left] >= rotatedArray[right])
     {
         if (right - left == )
         {
             middle = right;
             break;
         }
         middle = (left + right) / ;

         // 如果left、right、middle的值相同，只能顺序查找
         if (rotatedArray[left]==rotatedArray[middle]
         && rotatedArray[middle]==rotatedArray[right])
         {
             for (int i = left+; i < right; ++i)
             {
                 if (rotatedArray[i] < rotatedArray[i-])
                     return rotatedArray[i];
             }
             return rotatedArray[left];
         }

         if (rotatedArray[middle] >= rotatedArray[left])
             left = middle;
         else if (rotatedArray[middle] <= rotatedArray[right])
             right = middle;
     }
     return rotatedArray[middle];
 }

 int main()
 {
     int rotatedArray1[] = {,,,,,,};
     int rotatedArray2[] = {,,,,,,};
     int rotatedArray3[] = {,,,,,,};
     int rotatedArray4[] = {,,,,,,,,,};

     int length1 = ;
     int length2 = ;

     int ret1, ret2;

     ret1 = minNumberInRotatedArray1(rotatedArray1, length1);
     ret2 = minNumberInRotatedArray2(rotatedArray1, length1);
     printf("ret1 is %d, ret2 is %d\n", ret1, ret2);
     ret1 = minNumberInRotatedArray1(rotatedArray2, length1);
     ret2 = minNumberInRotatedArray2(rotatedArray2, length1);
     printf("ret1 is %d, ret2 is %d\n", ret1, ret2);
     ret1 = minNumberInRotatedArray1(rotatedArray3, length1);
     ret2 = minNumberInRotatedArray2(rotatedArray3, length1);
     printf("ret1 is %d, ret2 is %d\n", ret1, ret2);
     ret1 = minNumberInRotatedArray1(rotatedArray4, length2);
     ret2 = minNumberInRotatedArray2(rotatedArray4, length2);
     printf("ret1 is %d, ret2 is %d\n", ret1, ret2);

     return ;
 }