How to get the second largest number by not usings list and max()min()

Question

I want to find the second largest number such as this topic. Get the second largest number in a list in linear time

My problem is this restricting words list, [], remove, del, min, max, dict, {}, sort, pop.

I have no ideas to get the second largest number. Then, I want someone to suggest me.

Thanks!

If you are not using a list then where are you storing the numbers?? — jbsu32, Aug 30 '16 at 12:04
`print sorted(lst)[-2]` may be. Though I don't understand `don't use the list` part. — Ahsanul Haque, Aug 30 '16 at 12:08
Possible duplicate of [How can we find second maximum from array efficiently?](http://stackoverflow.com/questions/2392689/how-can-we-find-second-maximum-from-array-efficiently) — Lokesh Sanapalli, Aug 30 '16 at 12:12

score 2 · Answer 1 · edited May 23 '17 at 12:14

2

Not sure I've understood correctly your question but the post you've mentioned is giving you already few good solutions. For instance, if you don't want to code the algorithm by yourself, use the standard library heapq like this:

import random
import heapq

random.seed(1)
el = [random.randint(1, 100) for i in range(20)]
print el
first_max, second_max = heapq.nlargest(2, el)
print "Max element is {0} and the second max {1}".format(first_max,
second_max)

edited May 23 '17 at 12:14

Community

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answered Aug 30 '16 at 12:12

BPL

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`heapq` functions operate on lists, which he or she _can't_ use. – Kevin J. Chase Aug 30 '16 at 12:59

score 0 · Answer 2 · answered Aug 30 '16 at 12:07

first_max=arr[0]
second_max=first_max
if(arr[0]>arr[1]):
    first_max=arr[0]
    second_max=arr[1]
for i in range(1,len(arr)):
    if(arr[i]>first_max):
       second_max=first_max
       first_max=arr[i]
    elif(arr[i]>second_max):
       second_max=arr[i]

print(second_max)

I think above code will work for all cases... try and let me know.

jbsu32 · Answer 3 · 2016-08-30T12:18:42.460

0

Try this ->

a = [1,5,7,8,3,4,6,8,2,9]
x=-999999999999
n=999999999999
for i in a:
    if i>x:
        x=i
for i in a:
    if x-i!=0 and x-i<n:
        n=x-i
        ans=i
print ans

edited Aug 30 '16 at 12:18

answered Aug 30 '16 at 12:07

jbsu32

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How to get the second largest number by not usings list and max()min()

3 Answers3