Solution53-1.java

class Solution {
    public int search(int[] nums, int target) {
        // 搜索右边界 right
        int i = 0, j = nums.length - 1;
        while (i <= j) {
            int m = (i + j) / 2;
            if (nums[m] <= target)
                i = m + 1;
            else
                j = m - 1;
        }
        int right = i;
        // 若数组中无 target ，则提前返回
        if (j >= 0 && nums[j] != target)
            return 0;
        // 搜索左边界 right
        i = 0;
        j = nums.length - 1;
        while (i <= j) {
            int m = (i + j) / 2;
            if (nums[m] < target)
                i = m + 1;
            else
                j = m - 1;
        }
        int left = j;
        return right - left - 1;
    }
}

// 链接：https://leetcode-cn.com/problems/zai-pai-xu-shu-zu-zhong-cha-zhao-shu-zi-lcof/solution/mian-shi-ti-53-i-zai-pai-xu-shu-zu-zhong-cha-zha-5/