Add CountInMatrix method for Matrix struct

Author: terminalnode

common/util/matrix.go

@@ -7,8 +7,8 @@ import (
 
 type Matrix[T any] struct {
 	RawMatrix [][]T
-	MaxX   int
-	MaxY   int
+	MaxX      int
+	MaxY      int
 }
 
 type IntMatrix = Matrix[int]
@@ -42,8 +42,8 @@ func NewMatrixFromRows[T any](
 
 	return Matrix[T]{
 		RawMatrix: matrix,
-		MaxX:   maxX,
-		MaxY:   maxY,
+		MaxX:      maxX,
+		MaxY:      maxY,
 	}, nil
 }
 
@@ -103,3 +103,18 @@ func (m Matrix[T]) Set(
 	m.RawMatrix[y][x] = value
 	return nil
 }
+
+func CountInMatrix[T comparable](
+	m Matrix[T],
+	value T,
+) int {
+	count := 0
+	for x := 0; x <= m.MaxX; x++ {
+		for y := 0; y <= m.MaxY; y++ {
+			if m.RawMatrix[y][x] == value {
+				count += 1
+			}
+		}
+	}
+	return count
+}

common/util/matrix_test.go

@@ -258,3 +258,36 @@ func TestMatrix_Set(t *testing.T) {
 		})
 	}
 }
+
+func TestCountInMatrix(t *testing.T) {
+	m, err := NewMatrixFromRows([][]int{{1, 2, 3, 1}, {2, 3, 3, 1}, {3, 1, 2, 1}})
+	count1 := 5
+	count2 := 3
+	count3 := 4
+	count4 := 0
+
+	if err != nil {
+		t.Error("Failed to construct matrix")
+	}
+	var count int
+
+	count = CountInMatrix(m, 1)
+	if count != count1 {
+		t.Errorf("Expected %d number of ones, got %d", count1, count)
+	}
+
+	count = CountInMatrix(m, 2)
+	if count != count2 {
+		t.Errorf("Expected %d number of ones, got %d", count2, count)
+	}
+
+	count = CountInMatrix(m, 3)
+	if count != count3 {
+		t.Errorf("Expected %d number of ones, got %d", count3, count)
+	}
+
+	count = CountInMatrix(m, 4)
+	if count != count4 {
+		t.Errorf("Expected %d number of ones, got %d", count4, count)
+	}
+}