Question

How to find the sum of boundary elements of a matrix in JavaScript

Answer 1

function getBoundarySum(matrix) {
    const rows = matrix.length;
    const cols = matrix[0].length;
    let sum = 0;
    
    for (let i = 0; i < rows; i++) {
        for (let j = 0; j < cols; j++) {
            if (i == 0 || j == 0 || i == rows - 1 || j == cols - 1) {
                sum += matrix[i][j];
            }
        }
    }
    
    return sum;
}
        
const matrix = [[1, 2, 3, 4], 
                [5, 6, 7, 8], 
                [9, 10, 11, 12]];

console.log(getBoundarySum(matrix));




/*
run:
   
65
   
*/

 

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