44 lines
949 B
Java
44 lines
949 B
Java
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# 53. 数字在排序数组中出现的次数
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[NowCoder](https://www.nowcoder.com/practice/70610bf967994b22bb1c26f9ae901fa2?tpId=13&tqId=11190&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
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## 题目描述
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```html
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Input:
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nums = 1, 2, 3, 3, 3, 3, 4, 6
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K = 3
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Output:
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4
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```
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## 解题思路
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```java
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public int GetNumberOfK(int[] nums, int K) {
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int first = binarySearch(nums, K);
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int last = binarySearch(nums, K + 1);
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return (first == nums.length || nums[first] != K) ? 0 : last - first;
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}
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private int binarySearch(int[] nums, int K) {
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int l = 0, h = nums.length;
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while (l < h) {
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int m = l + (h - l) / 2;
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if (nums[m] >= K)
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h = m;
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else
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l = m + 1;
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}
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return l;
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}
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```
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<div align="center"><img width="320px" src="https://cs-notes-1256109796.cos.ap-guangzhou.myqcloud.com/githubio/公众号二维码-1.png"></img></div>
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