package q1975

import "math"

func abs(i int) int {
	if i < 0 {
		return -i
	}
	return i
}

func maxMatrixSum(matrix [][]int) int64 {
	var sum int64
	min_ := math.MaxInt
	hasZero := false
	nNeg := 0

	for i := range matrix {
		for _, num := range matrix[i] {
			if num < 0 {
				nNeg++
			}
			if num == 0 {
				hasZero = true
			}
			num = abs(num)
			sum += int64(num)
			if num < min_ {
				min_ = num
			}
		}
	}

	if hasZero || nNeg%2 == 0 {
		return sum
	}
	return sum - 2*int64(min_)
}

var _ = maxMatrixSum