Leetcode-1051: height checker

Title Description

The school plans to take an annual commemorative photo for all the students . According to the requirements , Students need to follow The decreasing Line up in order of height .
The sorted height is an integer array expected Express , among expected[i] It's expected to be number... In this line i The height of a student （ Subscript from 0 Start ）.
Give you an array of integers heights , Indicates the height of the current student position .heights[i] It's the... In this line i The height of a student （ Subscript from 0 Start ）.
Return to satisfaction heights[i] != expected[i] Number of subscripts for .

Example

Example 1：
Input ：heights = [1,1,4,2,1,3]
Output ：3
explain ：
Height ：[1,1,4,2,1,3]
expect ：[1,1,1,2,3,4]
Subscript 2 、4 、5 The height of the students at does not match .

Example 2：
Input ：heights = [5,1,2,3,4]
Output ：5
explain ：
Height ：[5,1,2,3,4]
expect ：[1,2,3,4,5]
The corresponding student heights of all subscripts do not match .

Example 3：
Input ：heights = [1,2,3,4,5]
Output ：0
explain ：
Height ：[1,2,3,4,5]
expect ：[1,2,3,4,5]
The corresponding student heights of all subscripts match .

The problem solving process

Ideas and steps

（1） Simple questions . Consider space for time .
（2） New development data , And sort in ascending order ;
（3） Traverse two arrays , Count the number of different elements in the same position between the sorted array and the original array , It's the end result .

Code display

public class HeightChecker {
    

    public int heightChecker(int[] heights) {
    
        //  Open up new data ,  Sort ,  Compare the new array data with the original array data 
        int[] tempArray = Arrays.copyOf(heights, heights.length);
        Arrays.sort(tempArray);
        int count = 0;
        for (int i = 0; i < heights.length; i++) {
    
            if (tempArray[i] != heights[i]) {
    
                count++;
            }
        }
        return count;
    }

    public static void main(String[] args) {
    
        int[] heights = {
    5,1,2,3,4,6};
        System.out.println(new HeightChecker().heightChecker(heights));
    }

}