1051. Height Checker

1051. Height Checker

 

A school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected[i] is the expected height of the ith student in line.

You are given an integer array heights representing the current order that the students are standing in. Each heights[i] is the height of the ith student in line (0-indexed).

Return the number of indices where heights[i] != expected[i].

 

Example 1:

Input: heights = [1,1,4,2,1,3]
Output: 3
Explanation: 
heights:  [1,1,4,2,1,3]
expected: [1,1,1,2,3,4]
Indices 2, 4, and 5 do not match.

Example 2:

Input: heights = [5,1,2,3,4]
Output: 5
Explanation:
heights:  [5,1,2,3,4]
expected: [1,2,3,4,5]
All indices do not match.

Example 3:

Input: heights = [1,2,3,4,5]
Output: 0
Explanation:
heights:  [1,2,3,4,5]
expected: [1,2,3,4,5]
All indices match.

Constraints:

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

 

Solution 나의 코드 [Runtime:  52ms, Memory Usage:  14MB]

[Runtime beats 11.97% of python 3 submission] [Memory usage beats 42.36% of python3 submission]

class Solution:
    def heightChecker(self, heights: List[int]) -> int:
        
        sort = sorted(heights)
        cnt = 0
        
        for i in range(len(heights)):
            if sort[i] != heights[i]:
                cnt += 1
                
        return cnt

Solution 나의 코드2 [Runtime:  20ms, Memory Usage:  14.2MB]

[Runtime beats 99.92% of python 3 submission] [Memory usage beats 42.36% of python3 submission]

class Solution:
    def heightChecker(self, heights: List[int]) -> int:
        
        cnt = 0
        
        for i, val in enumerate(sorted(heights)):
            if val != heights[i]:
                cnt += 1
                
        return cnt

enumerate() 사용하고 for문에 아예 sorted 함수를 넣으니까 런타임 속도 매우 빨라짐!!