Question

How to find the equilibrium index of a list (sum lst[0 to index - 1] == sum lst[index + 1 to size]) in Python

Answer 1

def getEquilibriumIndex(lst) :
    sum_arr = 0
    left_part_sum = 0
    size = len(lst)
    
    i = 0
    while (i < size) :
        sum_arr += lst[i]
        i += 1
    
    i = 0
    while (i < size) :
        sum_arr -= lst[i]
        if (left_part_sum == sum_arr) :
            return i
        left_part_sum += lst[i]
        i += 1
    
    return -1


lst = [-9, 2, 5, 8, -7, 4, 1]

print("equilibrium index = " + str(getEquilibriumIndex(lst)), end ="")




'''
run:

equilibrium index = 3

'''

 

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