// Package q1727 implements a solution for https://leetcode.com/problems/largest-submatrix-with-rearrangements/
package q1727

import "slices"

func largestSubmatrix(matrix [][]int) int {
	maxArea := 0

	// Count from the bottom the length of all contiguous segments of every column.
	for col := range matrix[0] {
		ones := 0
		for row := len(matrix) - 1; row >= 0; row-- {
			if matrix[row][col] == 0 {
				ones = 0
			} else {
				ones += 1
				matrix[row][col] = ones
			}
		}
	}

	for _, row := range matrix {
		slices.SortFunc(row, func(a, b int) int { return b - a })
		minLen := row[0]
		for col := range row {
			minLen = min(minLen, row[col])
			maxArea = max(maxArea, minLen*(col+1))
		}
	}
	return maxArea
}

var _ = largestSubmatrix