剑指 Offer 53 - I. 在排序数组中查找数字 I

题目描述：

示例 1:

示例 2:

题目分析：

1. 数组是有序的
2. 要统计target在数组中出现的次数

思路一：

代码实现：

class Solution {
    public int search(int[] nums, int target) {
        int len = nums.length;
        int count = 0;
        for (int i = 0; i < len; i++) {
            if (nums[i] == target) {
                count++;
            }
        }
        return count;
    }
}

思路二：

代码实现：

class Solution {
    public int search(int[] nums, int target) {
        int len = nums.length;
        if (len == 0) {
            return 0;
        }
        int left = binarySearch(nums, target);
        if (nums[left] != target) {
            return 0;
        }
        int mark = 0;
        for (int i = left; i < nums.length; i++) {
            if (nums[i] == target) {
                mark++;
            }
        }
        return mark;
    }

    public int binarySearch(int[] arr, int target) {
        int low = 0, high = arr.length - 1;
        while (low < high) {
            int mid = (high - low) / 2 + low;
            if (arr[mid] < target) {
                low = mid + 1;
            } else {
                high = mid;
            }
        }
        return low;
    }
}