Function numIslands

matrix/number-of-islands.js:3–15

(grid)

// time O(wh) where w is the width of the grid and h the height
// space O(n) where n is the number of items in our stack search
function numIslands(grid) {
  let numIslands = 0;

  for (let row = 0; row < grid.length; row++) {
    for (let col = 0; col < grid[row].length; col++) {
      if (grid[row][col] === "1") {
        search(grid, row, col);
        numIslands++;
      }
    }
  }
  return numIslands;
}

function search(grid, row, col) {
  const stack = [[row, col]];