1034-coloring-a-border.js

/**
 * @param {number[][]} grid
 * @param {number} r0
 * @param {number} c0
 * @param {number} color
 * @return {number[][]}
 */
const colorBorder = function(grid, r0, c0, color) {
  const dirs = [[-1,0], [1,0], [0,1], [0,-1]]
  const c = grid[r0][c0]
  const rows = grid.length
  const cols = grid[0].length
  const visited = Array.from({length: rows}, () => new Array(cols).fill(0))
  dfs(r0, c0, c, rows, cols, visited, grid, dirs)
  for(let i = 0; i < rows; i++) {
    for(let j = 0; j < cols; j++) {
      if(visited[i][j] === -1) {
         if(i === 0 || j === 0 || i === rows - 1 || j === cols - 1) {
            visited[i][j] = -2
         } else {
            for(let dir of dirs) {
              if(visited[i + dir[0]][j + dir[1]] === 0) {
                 visited[i][j] = -2
                 break
              }
            }    
         }
      }
    }
  }
  for(let i = 0; i < rows; i++) {
    for(let j = 0; j < cols; j++) {
      if(visited[i][j] === -2) grid[i][j] = color
    }
  }
  
  return grid
};

function dfs(row, col, target, rows, cols, visited, grid, dirs) {
  if(row >= rows || col >= cols || row < 0 || col < 0 || grid[row][col] !== target || visited[row][col] === -1) {
    return   
  }
  visited[row][col] = -1
  for(let dir of dirs) {
    dfs(row + dir[0], col+dir[1], target, rows, cols, visited, grid, dirs)
  }
  
}