Find peaks inside matrix

Given a 2D matrix of integers, find and return any "peak" element within the matrix. A peak element is an element in the matrix that is greater than or equal to all of its adjacent neighbors. Adjacent neighbors are the elements directly to its left, right, top, and bottom. For elements at the edges or corners of the matrix, missing neighbors are considered to have a value of negative infinity.

Hint

Examines each number in the matrix and checks if it's larger than all its immediate neighbors (above, below, left, and right). If it is, that number is considered a peak.

• Python
• Javascript
•  Run

matrix = [
  [ 1, 2, 3 ], 
  [ 4, 9, 6 ],
  [ 7, 8, 5 ]
]
  
output = []
h = len(matrix)
w = len(matrix[0])

for i in range(h):
  for j in range(w):
    t = float('-inf') if i - 1 < 0 else matrix[i - 1][j]
    l = float('-inf') if j - 1 < 0 else matrix[i][j - 1]
    b = float('-inf') if i + 1 >= h else  matrix[i + 1][j]
    r = float('-inf') if j + 1 >= w else matrix[i][j + 1]

    c = matrix[i][j]

    if c > t and c > l and c > b and c > r:
      output.append([i, j])

print(output)

const matrix = [
  [ 1, 2, 3 ], 
  [ 4, 9, 6 ],
  [ 7, 8, 5 ]
];
  
const output = [];
const h = matrix.length;
const w = matrix[0].length;

for (let i = 0; i < h; i++) {
  for (let j = 0; j < w; j++) {
    let t = (i-1 < 0) ? -Infinity : matrix[i - 1][j];
    let l = (j-1 < 0) ? -Infinity : matrix[i][j - 1];
    let b = (i+1 >= h) ? -Infinity : matrix[i + 1][j];
    let r = (j+1 >= w) ? -Infinity : matrix[i][j + 1];

    let c = matrix[i][j];

    if (c > t && c > l && c > b && c > r) {
      output.push([i, j]);
    }
  }
}

console.log(output);