Only my personal opinions, hope they can help you.☺

If you stuck on WA#3, try the following understanding:
The description said "A component of a salad could be a basic ingredient or [another] salad", but Test 3 may contain some cases in which the component of a salad is this salad itself.

If you stuck on WA#6, please remember that "Percentages should be output with an absolute or relative error no more than 10−3"

сабж, кроме того что он достаточно большой