All files / leetCode 0085.ts

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import largestRectangleArea from './0084'
 
export default function maximalRectangle(matrix: string[][]): number {
  if (matrix.length === 0 || matrix[0].length === 0)
    return 0
 
  const m = matrix.length
  const n = matrix[0].length
  const heights = Array.from<number>({ length: m }).map(() => Array.from<number>({ length: n }).fill(0))
 
  // Use dynamic programming to calculate heights of `m` histograms
  for (let i = 0; i < m; i++) {
    for (let j = 0; j < n; j++) {
      if (matrix[i][j] === '1')
        heights[i][j] = i === 0 ? 1 : heights[i - 1][j] + 1
    }
  }
 
  let res = 0
 
  for (let i = 0; i < m; i++)
    res = Math.max(res, largestRectangleArea(heights[i]))
 
  return res
}