minimize the number of guesses to reduce non-polynomial time component

main.go

@@ -157,6 +157,7 @@ func eliminate(field *field) *int {
 }
 
 type result int
+
 const (
 	unsolved result = iota
 	solved
@@ -192,20 +193,31 @@ func copyField(fieldToCopy field) field {
 }
 
 func addGuesses(field field) {
+	hasGuess := false
+	minX := 0
+	minY := 0
+	minLength := size + 1
+
 	for x := 0; x < size; x++ {
 		for y := 0; y < size; y++ {
-			if len(field[x][y]) > 1 {
-				for _, value := range field[x][y] {
+			length := len(field[x][y])
+			if length > 1 && length < minLength {
+				hasGuess = true
+				minX = x
+				minY = y
+				minLength = length
+			}
+		}
+	}
+
+	if hasGuess {
+		for _, value := range field[minX][minY] {
 			newField := copyField(field)
-					newField[x][y] = []int{value}
+			newField[minX][minY] = []int{value}
 
 			atomic.AddInt64(&possibilities, 1)
 			guesses <- newField
 		}
-				// we don't need to add more
-				return
-			}
-		}
 	}
 }