Comparing two lists and "looking back"

How would you approach comparing two lists and "looking back"?

I'm comparing the elements of two lists like this:

score = 0
for (x,y) in zip(seqA,seqB):

    if x == y:
        score = score +1

    if x !=y :
        score = 开发者_开发百科score - 1

Now I would like score + 3 if the previous pair was a match, so basically I would have to "look back" one iteration.

Just save the result of the last match.

score = 0
prev  = 0

for (x,y) in zip(seqA,seqB):

    if x == y:
        if prev == 1:
            score = score +3
        else:
            score = score +1
        prev = 1

    if x !=y :
        score = score - 1
        prev = 0

There may be a more direct way, but being explicit is not bad either.
The idea to add introduce a variable which tells which amount to add next time we have a match.

score = 0
matchPts = 1                   // by default, we add 1
for (x,y) in zip(seqA,seqB):

    if x == y:
        score = score + matchPts 
        matchPts = 3 

    if x !=y :
        score = score - 1
        matchPts = 1

A more sophisticated reward scale for multiple consecutive matches could be introduced with a few changes:

score = 0
consecutiveMatches = 0 
for (x,y) in zip(seqA,seqB):

    if x == y:
        consecutiveMatches += 1 
        reward = 1
        if consecutiveMatches == 2:
           reward = 3;
        if consecutiveMatches > 2 :
           reward = 5;
        if consecutiveMatches > 5 :
           reward = 100;     // jackpot ;-)
        // etc.
        score += reward
    else:
        score -=  1
        consecutiveMatches  = 0

score = 0
previousMatch == False
for (x,y) in zip(seqa, seqb):
    if x==y && previousMatch:
        score += 3
    elif x==y:
        score += 1
        previousMatch = True
    else:
        score -= 1
        prviousMatch = False

Similar to how others have done this, but I'd rather use variable names like "correct" rather than seeing "x == y" all over the place...

# Create a list of whether an answer was "correct".
results = [x == y for (x,y) in zip(seqA, seqB)]

score = 0
last_correct = False
for current_correct in results:
    if current_correct and last_correct:
        score += 3
    elif current_correct:
        score += 1
    else:
        score -= 1

    last_correct = current_correct

print score