Height Checker

LeetCode Q 1051 - Height Checker

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

Return the minimum number of students not standing in the right positions. (This is the number of students that must move in order for all students to be standing in non-decreasing order of height.)

Example 1: Input: [1,1,4,2,1,3] ; Output: 3
Explanation: Students with heights 4, 3 and the last 1 are not standing in the right positions.

Note:

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

Solution

• clone the original array and sort it.
• compare each number in the new array and original array, if they are not equal, one more student stands in the wrong position.

Code:

public int heightChecker(int[] heights) {

  int[] copy = heights.clone();
  
  Arrays.sort(copy);

  int res = 0;

  for (int i = 0; i < heights.length; i++) {
    if (heights[i] != copy[i])
      res++;
  }

  return res;
}