freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-javascript/6a0dcd03ee4e68698080ef6b.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6a0dcd03ee4e68698080ef6b	Challenge 307: Zoning Regulations	28	challenge-307

--description--

Given a 2D grid (array of arrays) representing a city's building layout, return the coordinates of all buildings that are violating zoning rules.

Each cell in the grid contains one of the labels from the table below. A building is in violation if any of its (up to) 4 neighbors, horizontal or vertical, are a type it cannot be adjacent to.

Label	Type	Cannot be adjacent to
"i"	industrial	"R", "I"
"A"	Agricultural	"C"
"R"	Residential	"i", "C"
"I"	Institutional	"i"
"C"	Commercial	"R", "A"
"" (empty string)	undeveloped	no restrictions

Return the coordinates of all violating cells as an array of [row, col] pairs, in any order. If no violations exist, return an empty array.

--hints--

getZoneViolations([["R", "C"], ["", "C"]]) should return [[0, 0], [0, 1]].

assert.deepEqual(getZoneViolations([["R", "C"], ["", "C"]]).sort(), [[0, 0], [0, 1]]);

getZoneViolations([["", "i"], ["", "R"], ["R", "I"]]) should return [[0, 1], [1, 1]].

assert.deepEqual(getZoneViolations([["", "i"], ["", "R"], ["R", "I"]]).sort(), [[0, 1], [1, 1]]);

getZoneViolations([["A", "i", "C"], ["A", "", "C"], ["R", "R", "I"]]) should return [].

assert.deepEqual(getZoneViolations([["A", "i", "C"], ["A", "", "C"], ["R", "R", "I"]]).sort(), []);

getZoneViolations([["R", "R", "C", "R", "R"], ["R", "I", "C", "", "A"], ["R", "R", "", "i", "A"]]) should return [[0, 1], [0, 2], [0, 3]].

assert.deepEqual(getZoneViolations([["R", "R", "C", "R", "R"], ["R", "I", "C", "", "A"], ["R", "R", "", "i", "A"]]).sort(), [[0, 1], [0, 2], [0, 3]]);

getZoneViolations([["R", "A", "A", "", "i", "i"], ["R", "I", "", "C", "i", "i"], ["R", "", "C", "C", "A", "A"], ["R", "R", "C", "I", "R", "R"]]) should return [[2, 3], [2, 4], [3, 1], [3, 2]].

assert.deepEqual(getZoneViolations([["R", "A", "A", "", "i", "i"], ["R", "I", "", "C", "i", "i"], ["R", "", "C", "C", "A", "A"], ["R", "R", "C", "I", "R", "R"]]).sort(), [[2, 3], [2, 4], [3, 1], [3, 2]]);

--seed--

--seed-contents--

function getZoneViolations(grid) {

  return grid;
}

--solutions--

function getZoneViolations(grid) {
  const rules = {
    "i": ["R", "I"],
    "A": ["C"],
    "R": ["i", "C"],
    "I": ["i"],
    "C": ["R", "A"],
    "": []
  };

  const directions = [[-1, 0], [0, -1], [0, 1], [1, 0]];
  const violations = [];

  for (let row = 0; row < grid.length; row++) {
    for (let col = 0; col < grid[row].length; col++) {
      const cell = grid[row][col];
      const forbidden = rules[cell];

      for (const [dr, dc] of directions) {
        const nr = row + dr;
        const nc = col + dc;
        if (nr >= 0 && nr < grid.length && nc >= 0 && nc < grid[row].length) {
          if (forbidden.includes(grid[nr][nc])) {
            violations.push([row, col]);
            break;
          }
        }
      }
    }
  }

  return violations;
}