add new solutions

solutions/19/q1975/solution.go

@@ -0,0 +1,40 @@
+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