I need to find a longest sequence of 5's in a list user_scores = [1, 5, 5, 1, 5, 5, 5, 2, 5, 5, 1, 5] without using any libraries or built in functions (like max)

My solution is

key = 5
max_sequence = 0
current_sequence = 0
new_sequence = 0
for score in user_scores:
    if score == key:
        current_sequence  = 1
        current_sequence = max_sequence
    elif score != key:
        current_sequence = 0
else:
    print(max_sequence)

Obviously it doesn't work at all. Trying my best to learn algorithms so i would appreciate an explanation with a code.

CodePudding user response：

Hope the explanation in comment will make it clear, if not please ask I'll make a more detailed answer :)

user_scores = [1, 5, 5, 1, 5, 5, 5, 2, 5, 5, 1, 5]
key = 5
max_sequence = 0
current_sequence = 0
for score in user_scores:
    if score == key:
        #If it's the right key then you found another one in the sequence 
        current_sequence  = 1
    else:
        #Otherwise you'r not in a sequence so current_sequence size is empty 
        current_sequence = 0

    if current_sequence > max_sequence:
        #If the current sequence size is bigger than the max then it's the new max
        max_sequence = current_sequence

print(max_sequence)

CodePudding user response：

You can try this:

1. If you reach to different num reset long_seq.
2. If updating long_seq save this update in max_seq (if larger than previous longest sequense).

like below:

user_scores = [1, 5, 5, 1, 5, 5, 5, 2, 5, 5, 1, 5]

def find_long_seq(arr, key):
    long_seq = 0
    max_seq = 0
    for num in arr:
        if num == key:
            long_seq  = 1
            if long_seq > max_seq:
                max_seq = long_seq
        elif num != key:
            long_seq = 0

    return max_seq
    
print(find_long_seq(user_scores, 5))

Output:

3

CodePudding user response：

l = [1, 5, 5, 1, 5, 5, 5, 2, 5, 5, 1, 5]

MAX, counter = 0, 0
for i in l:
    if i != 5:
        if counter > MAX:
            MAX = counter
        counter = 0  # reset
    else:
        counter  = 1 # increment if 5 is matched

# final fix
if counter > MAX:
    MAX = counter

print(MAX)

If lists are allowed:

l = [1, 5, 5, 1, 5, 5, 5, 2, 5, 5, 1, 5]

a = []
for i in l:
    if i != 5:
        a.append(0)
    else:
        a[-1]  = 1

MAX = 0
for i in a:
    if i > MAX:
        MAX = i
print(MAX)

CodePudding user response：

You don't need to add an elif and current_sequence .Try this.

user_scores = [1, 5, 5, 1, 5, 5, 5, 2, 5, 5, 1, 5]

key= 5
max_sequence = 0
new_sequence = 0

for score in user_scores: 
    if score ==key:
        if new_sequence==max_sequence:
            new_sequence  = 1
            max_sequence =new_sequence

        else:
            new_squence  = 1

    else:
        new_sequence = 0

print(max_secquence)

output

3