# 1051. Height Checker

Students are asked to stand in non-decreasing order of heights for an annual photo.

Return the minimum number of students that must move in order for all students to be standing in non-decreasing order of height.

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.

Example 1:

``````Input: heights = [1,1,4,2,1,3]
Output: 3
Explanation:
Current array : [1,1,4,2,1,3]
Target array  : [1,1,1,2,3,4]
On index 2 (0-based) we have 4 vs 1 so we have to move this student.
On index 4 (0-based) we have 1 vs 3 so we have to move this student.
On index 5 (0-based) we have 3 vs 4 so we have to move this student.
``````

Example 2:

``````Input: heights = [5,1,2,3,4]
Output: 5
``````

Example 3:

``````Input: heights = [1,2,3,4,5]
Output: 0
``````

Constraints:

• `1 <= heights.length <= 100`
• `1 <= heights[i] <= 100`

``````class Solution {
public:
int heightChecker(vector<int>& heights) {
int res = 0, n = heights.size();
vector<int> sorted = heights;
sort(sorted.begin(), sorted.end());
for (int i = 0; i < n; ++i) {
if (sorted[i] != heights[i]) ++res;
}
return res;
}
};
``````

Github 同步地址:

https://github.com/grandyang/leetcode/issues/1051

https://leetcode.com/problems/height-checker/

https://leetcode.com/problems/height-checker/discuss/299221/C%2B%2B-Sort

https://leetcode.com/problems/height-checker/discuss/299216/Java-Sort-1ms-O(nlogn)

LeetCode All in One 题目讲解汇总(持续更新中…)

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