数字在排序数组中出现的次数

统计一个数字在排序数组中出现的次数。

/*
 * 受不了。。。。。。
 */
public class Solution {
    public int GetNumberOfK(int [] array , int k) {
        int count=0;
        for(int i=0;i<array.length;i++){
            if(array[i]==k)
                count++;
        }
        return count;
    }
}

不用递归会死的。

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public int GetNumberOfK(int [] array , int k) {        if (array == null || array.length == 0)             return 0;           int l = 0, h = array.length - 1, m1 = 0, m2 = 0;                   if (l == h)             if (array[0] != k)                 return 0;             else             return 1;                   while (l < h) {             int mid = (l + h) / 2;             if (array[mid] < k) {                 if (array[mid + 1] == k) {                     m1 = mid;                     break;                 }                 l = mid + 1;             } else {                 h = mid;                 m1 = -1;             }         }                   if (array[m1+1] != k)   // can't find it.             return 0;           l = 0;         h = array.length - 1;         while (l < h) {             int mid = (l + h) / 2;             if (array[mid] <= k) {                 m2 = mid;                 if (array[mid + 1] > k)                     break;                 else {                     if (mid + 1 >= h) {                         m2++;                         break;                     }                     l = mid + 1;                 }             } else                 h = mid;         }         return m2 - m1;     }

用递归：

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public int GetNumberOfK(int[] array, int k) {         if (array == null || array.length == 0)             return 0;                   int t = getFirst(array, 0, array.length - 1, k);         if (t != -1)             return getLast(array, 0, array.length - 1, k) - t + 1;                   return 0;     }       int getFirst(int[] array, int s, int e, int k) {         if (s >= e)             return array[s] == k ? s : -1;                   int m = (s + e) / 2;         if (array[m] < k)             return getFirst(array, m + 1, e, k);         else             return getFirst(array, s, m, k);     }       int getLast(int[] array, int s, int e, int k) {         if (s >= e) {             if (array[s] == k)                 return s;             return array[s - 1] == k ? s - 1 : -1;         }                   int m = (s + e) / 2;         if (array[m] <= k)             return getLast(array, m + 1, e, k);         else             return getLast(array, s, m, k);     }