Question

1051. Height Checker

中文文档

Description

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

Solutions

Solution 1

class Solution:
  def heightChecker(self, heights: List[int]) -> int:
    expected = sorted(heights)
    return sum(a != b for a, b in zip(heights, expected))

class Solution {
  public int heightChecker(int[] heights) {
    int[] expected = heights.clone();
    Arrays.sort(expected);
    int ans = 0;
    for (int i = 0; i < heights.length; ++i) {
      if (heights[i] != expected[i]) {
        ++ans;
      }
    }
    return ans;
  }
}

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

func heightChecker(heights []int) int {
  expected := make([]int, len(heights))
  copy(expected, heights)
  sort.Ints(expected)
  ans := 0
  for i, v := range heights {
    if v != expected[i] {
      ans++
    }
  }
  return ans
}

Solution 2

class Solution:
  def heightChecker(self, heights: List[int]) -> int:
    cnt = [0] * 101
    for h in heights:
      cnt[h] += 1
    ans = i = 0
    for j in range(1, 101):
      while cnt[j]:
        cnt[j] -= 1
        if heights[i] != j:
          ans += 1
        i += 1
    return ans

class Solution {
  public int heightChecker(int[] heights) {
    int[] cnt = new int[101];
    for (int h : heights) {
      ++cnt[h];
    }
    int ans = 0;
    for (int i = 0, j = 0; i < 101; ++i) {
      while (cnt[i] > 0) {
        --cnt[i];
        if (heights[j++] != i) {
          ++ans;
        }
      }
    }
    return ans;
  }
}

class Solution {
public:
  int heightChecker(vector<int>& heights) {
    vector<int> cnt(101);
    for (int& h : heights) ++cnt[h];
    int ans = 0;
    for (int i = 0, j = 0; i < 101; ++i) {
      while (cnt[i]) {
        --cnt[i];
        if (heights[j++] != i) ++ans;
      }
    }
    return ans;
  }
};

func heightChecker(heights []int) int {
  cnt := make([]int, 101)
  for _, h := range heights {
    cnt[h]++
  }
  ans := 0
  for i, j := 0, 0; i < 101; i++ {
    for cnt[i] > 0 {
      cnt[i]--
      if heights[j] != i {
        ans++
      }
      j++
    }
  }
  return ans
}