67 lines
1.9 KiB
Java
67 lines
1.9 KiB
Java
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//统计一个数字在排序数组中出现的次数。
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//
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//
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//
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// 示例 1:
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//
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// 输入: nums = [5,7,7,8,8,10], target = 8
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//输出: 2
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//
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// 示例 2:
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//
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// 输入: nums = [5,7,7,8,8,10], target = 6
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//输出: 0
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//
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//
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//
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// 限制：
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//
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// 0 <= 数组长度 <= 50000
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//
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//
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//
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// 注意：本题与主站 34 题相同（仅返回值不同）：https://leetcode-cn.com/problems/find-first-and-last-
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//position-of-element-in-sorted-array/
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// Related Topics 数组 二分查找
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// 👍 179 👎 0
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package leetcode.editor.cn;
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//剑指 Offer 53 - I:在排序数组中查找数字 I
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class ZaiPaiXuShuZuZhongChaZhaoShuZiLcof {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new ZaiPaiXuShuZuZhongChaZhaoShuZiLcof().new Solution();
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System.out.println(solution.search(new int[]{5, 7, 7, 8, 8, 10}, 6));
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System.out.println(solution.search(new int[]{5, 7, 7, 8, 8, 10}, 8));
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class Solution {
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public int search(int[] nums, int target) {
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int start = binarySearch(nums, target, true);
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int end = binarySearch(nums, target, false) - 1;
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if (start <= end && end < nums.length && nums[start] == target && nums[end] == target) {
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return end - start + 1;
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}
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return 0;
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}
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public int binarySearch(int[] nums, int target, boolean lower) {
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int start = 0, end = nums.length - 1, ans = nums.length;
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while (start <= end) {
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int mid = (start + end) / 2;
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if (nums[mid] > target || (lower && nums[mid] >= target)) {
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end = mid - 1;
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ans = mid;
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} else {
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start = mid + 1;
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}
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}
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return ans;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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}
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