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68 lines
1.9 KiB
Markdown
68 lines
1.9 KiB
Markdown
# [1051. Height Checker](https://leetcode.com/problems/height-checker/)
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## 题目
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Students are asked to stand in non-decreasing order of heights for an annual photo.
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Return the minimum number of students that must move in order for all students to be standing in non-decreasing order of height.
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Notice that when a group of students is selected they can reorder in any possible way between themselves and the non selected students remain on their seats.
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**Example 1**:
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```
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Input: heights = [1,1,4,2,1,3]
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Output: 3
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Explanation:
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Current array : [1,1,4,2,1,3]
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Target array : [1,1,1,2,3,4]
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On index 2 (0-based) we have 4 vs 1 so we have to move this student.
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On index 4 (0-based) we have 1 vs 3 so we have to move this student.
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On index 5 (0-based) we have 3 vs 4 so we have to move this student.
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```
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**Example 2**:
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```
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Input: heights = [5,1,2,3,4]
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Output: 5
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```
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**Example 3**:
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```
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Input: heights = [1,2,3,4,5]
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Output: 0
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```
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**Constraints**:
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- `1 <= heights.length <= 100`
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- `1 <= heights[i] <= 100`
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## 题目大意
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学校在拍年度纪念照时，一般要求学生按照 非递减 的高度顺序排列。请你返回能让所有学生以 非递减 高度排列的最小必要移动人数。注意，当一组学生被选中时，他们之间可以以任何可能的方式重新排序，而未被选中的学生应该保持不动。
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## 解题思路
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- 给定一个高度数组，要求输出把这个数组按照非递减高度排列所需移动的最少次数。
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- 简单题，最少次数意味着每次移动，一步到位，一步就移动到它所在的最终位置。那么用一个辅助排好序的数组，一一比对计数即可。
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## 代码
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```go
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func heightChecker(heights []int) int {
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result, checker := 0, []int{}
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checker = append(checker, heights...)
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sort.Ints(checker)
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for i := 0; i < len(heights); i++ {
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if heights[i] != checker[i] {
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result++
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}
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}
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return result
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}
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``` |