ANKUR AGGARWAL wrote:
> Hey
> I am looking for an algo for the largest sequence search in the two list.
>
> Example : list a accepts some say 'm' numbers. list b accept says 'n'
> numbers. I want to look for the largest same sequence between the two list
> and then display it. I tried out but failed to do so.
> Say A=[11,23,45,21,63,56,78,32]
> B=[56,78,11,23,45,21,111,234,56543]
>
> There are two similar sequence matching over here [11,23] and [23,45,21]
> i want to display second sequence because its larger in number. Plz help
> Thanks in Advance :)
The following is not particular efficient, but may be good enough if the
sequences are not too long:
def index(items, value):
"""Generate all occurences of `value` in `items`"""
start = 0
while True:
try:
pos = items.index(value, start)
except ValueError:
break
yield pos
start = pos + 1
def matches(a, b):
for i, x in enumerate(a):
for k in index(b, x):
for p, (s, t) in enumerate(zip(a[i:], b[k:])):
if s != t:
break
yield a[i:i+p]
if __name__ == "__main__":
a = [11, 23, 45, 21, 63, 56, 78, 32]
b = [56, 78, 11, 23, 45, 21, 111, 234, 56543]
print(max(matches(a, b), key=len))
print(sorted(matches(a, b)))
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