reshape-the-matrix

This commit is contained in:
Gleb Koval 2022-05-31 22:54:52 +01:00
parent c85bf9b307
commit 365cacbd42
Signed by: cyclane
GPG Key ID: 15E168A8B332382C
2 changed files with 37 additions and 0 deletions

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// This is a more functional solution that I think
// is a bit easier to read, but does iterate over
// the matrix twice (two `Iter.collect()`s). So without
// compiler optimisations it might be a bit slower.
//
// I don't actually know whether this is true or not.
impl Solution {
pub fn matrix_reshape(mat: Vec<Vec<i32>>, r: i32, c: i32) -> Vec<Vec<i32>> {
let (m, n) = (mat.len(), mat[0].len());
if m*n != (r*c) as usize || m == r as usize{
return mat;
}
mat.into_iter()
.flatten()
.collect::<Vec<_>>()
.chunks(c as usize)
.map(|row| row.to_vec())
.collect::<Vec<_>>()
}
}

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// A solution using loops and still pretty
// easy to understand, and iterates over the
// matrix only once.
impl Solution {
pub fn matrix_reshape(mat: Vec<Vec<i32>>, r: i32, c: i32) -> Vec<Vec<i32>> {
let (m, n) = (mat.len(), mat[0].len());
let (r, c) = (r as usize, c as usize);
if m*n != r*c || m == r {
return mat;
}
let mut reshaped_matrix = vec![vec![0; c]; r];
for idx in (0..m*n) {
reshaped_matrix[idx / c][idx % c] = mat[idx / n][idx % n];
}
reshaped_matrix
}
}