Beginner Exercism • javascript

Rectangles

Challenge Overview

Count the rectangles in an ASCII diagram like the one below.

Source: Exercism javascript/rectangles

💡 View Solution

export function count(grid) {
  let rectangles = 0;
  const rows = grid.length;
  if (rows === 0) return 0;
  const cols = grid[0].length;

  for (let r1 = 0; r1 < rows; r1++) {
    for (let c1 = 0; c1 < cols; c1++) {
      if (grid[r1][c1] === '+') {
        for (let r2 = r1 + 1; r2 < rows; r2++) {
          if (grid[r2][c1] !== '+' && grid[r2][c1] !== '|') break;
          if (grid[r2][c1] === '+') {
            for (let c2 = c1 + 1; c2 < cols; c2++) {
              if (grid[r1][c2] === '+' && grid[r2][c2] === '+') {
                // Check if all edges are valid
                let valid = true;
                for (let r = r1 + 1; r < r2; r++) {
                  if ((grid[r][c1] !== '+' && grid[r][c1] !== '|') ||
                      (grid[r][c2] !== '+' && grid[r][c2] !== '|')) {
                    valid = false;
                    break;
                  }
                }
                if (!valid) continue;
                for (let c = c1 + 1; c < c2; c++) {
                  if ((grid[r1][c] !== '+' && grid[r1][c] !== '-') ||
                      (grid[r2][c] !== '+' && grid[r2][c] !== '-')) {
                    valid = false;
                    break;
                  }
                }
                if (valid) rectangles++;
              }
            }
          }
        }
      }
    }
  }
  return rectangles;
}