### 2545. Sort the Students by Their Kth Score leetcode problem Solution c++ | How to sort 2D vectors in c++ using a custom comparator in c++

## 2545. Sort the Students by Their Kth Score Solution c++-

### How to sort 2D vectors in c++ using a custom comparator in c++.

#### problem statement -

There is a class with `m`

students and `n`

exams. You are given a 0-indexed `m x n`

integer matrix `score`

, where each row represents one student and `score[i][j]`

denotes the score the `ith`

student got in the `jth`

exam. The matrix `score`

contains distinct integers only.

You are also given an integer `k`

. Sort the students (i.e., the rows of the matrix) by their scores in the `kth`

(0-indexed) exam from the highest to the lowest.

Return *the matrix after sorting it.*

Example 1:

```
Input: score = [[10,6,9,1],[7,5,11,2],[4,8,3,15]], k = 2
Output: [[7,5,11,2],[10,6,9,1],[4,8,3,15]]
Explanation: In the above diagram, S denotes the student, while E denotes the exam.
- The student with index 1 scored 11 in exam 2, which is the highest score, so they got first place.
- The student with index 0 scored 9 in exam 2, which is the second highest score, so they got second place.
- The student with index 2 scored 3 in exam 2, which is the lowest score, so they got third place.
```

Example 2:

```
Input: score = [[3,4],[5,6]], k = 0
Output: [[5,6],[3,4]]
Explanation: In the above diagram, S denotes the student, while E denotes the exam.
- The student with index 1 scored 5 in exam 0, which is the highest score, so they got first place.
- The student with index 0 scored 3 in exam 0, which is the lowest score, so they got second place.
```

Constraints:

`m == score.length`

`n == score[i].length`

`1 <= m, n <= 250`

`1 <= score[i][j] <= 105`

`score`

consists of distinct integers.`0 <= k < n`

# Explanation

# Complexity

```
public int[][] sortTheStudents(int[][] A, int k) {
Arrays.sort(A, (a, b) -> b[k] - a[k]);
return A;
}
```

```
vector<vector<int>> sortTheStudents(vector<vector<int>>& A, int k) {
sort(A.begin(), A.end(), [&](auto const & a, auto const & b) {
return a[k] > b[k];
});
return A;
}
```

` `

static int i=0;

```
def sortTheStudents(self, A, k):
return sorted(A, key=lambda a: -a[k])
```

## Comments

## Post a Comment