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Find Indexs of 0 to be replaced with 1 to get longest continuous sequence of 1s in a binary array - Set-2 in Python
Suppose we have one binary array. We have to find the position of 0 that can be replaced with 1 to get maximum number of continuous sequence of 1s.
So, if the input is like [1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1], then the output will be 10, so the array will be [1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1].
To solve this, we will follow these steps −
i := 0,
n := size of A
count_left := 0, count_right := 0
max_i := -1, last_i := -1
count_max := 0
while i < n, do
if A[i] is same as 1, then
count_right := count_right + 1
otherwise,
if last_i is not same as -1, then
if count_right + count_left + 1 > count_max, then
count_max := count_left + count_right + 1
max_i := last_i
last_i := i
count_left := count_right
count_right := 0
i := i + 1
if last_i is not same as -1, then
if count_left + count_right + 1 > count_max, then
count_max := count_left + count_right + 1
max_i := last_i
return max_i
Example
Let us see the following implementation to get better understanding −
def find_max_one_index(A): i = 0 n = len(A) count_left = 0 count_right = 0 max_i = -1 last_i = -1 count_max = 0 while i < n: if A[i] == 1: count_right += 1 else: if last_i != -1: if count_right + count_left + 1 > count_max: count_max = count_left + count_right + 1 max_i = last_i last_i = i count_left = count_right count_right = 0 i += 1 if last_i != -1: if count_left + count_right + 1 > count_max: count_max = count_left + count_right + 1 max_i = last_i return max_i A = [1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1] print(find_max_one_index(A))
Input
[1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1]
Output
10
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