当条件满足时，Python break语句不会终止程序

Question

I am trying to solve Two Sum II on Leet Code. The input is a sorted ascending list and a target value. My algorithm is supposed to output two indices of the elements that adds up to the target value. I am trying to use binary search for my implementation and here is my code:

def twoSum(nums, target):
    total_array_index = len(nums)-1

    current_index = 0

    binary_start_index = current_index + 1
    binary_end_index = total_array_index
    binary_mid_index = (binary_start_index+binary_end_index)/2

    current_sum = nums[current_index]+nums[binary_mid_index]


    while current_sum is not target:
        #exit out the loop if no solution is found
        if current_index == total_array_index:
            print('no solution found!')
            break

        while (binary_start_index<=binary_end_index):
            #condition meets, but "break" statement does not terminate loop ONLY when input list is large
            if current_sum == target:
                current_index = current_index-1
                break

            if current_sum > target:
                binary_end_index = binary_mid_index - 1
                binary_mid_index = (binary_start_index+binary_end_index)/2
                current_sum = nums[current_index]+nums[binary_mid_index]

            else:
                binary_start_index = binary_mid_index + 1
                binary_mid_index = (binary_start_index+binary_end_index)/2
                current_sum = nums[current_index]+nums[binary_mid_index]


        current_index = current_index + 1
        binary_start_index = current_index + 1
        binary_end_index = total_array_index
        current_sum = nums[current_index]+nums[binary_mid_index]


    return [current_index,binary_mid_index]

While I did passed 7/16 tests, but it times out on the 8th test with a really large input. I do not think it's the algorithm's issue. After trying to manually print out both 'current_index' and 'binary_mid_index', my program did successfully found the right indices that gave me the correct 'current_sum'. But the program simply won't 'break' out of the while loop when the input list is large. Is this something relate to Python?

Here is the testing input:

nums=[12,13,23,28,43,44,59,60,61,68,70,86,88,92,124,125,136,168,173,173,180,199,212,221,227,230,277,282,306,314,316,321,325,328,336,337,363,365,368,370,370,371,375,384,387,394,400,404,414,422,422,427,430,435,457,493,506,527,531,538,541,546,568,583,585,587,650,652,677,691,730,737,740,751,755,764,778,783,785,789,794,803,809,815,847,858,863,863,874,887,896,916,920,926,927,930,933,957,981,997]

target = 542

Answer 1

break only breaks you out of its current while loop, not the outer one.

You use multiple while s - you need to set the inner break condition on the outer while as well and combine its 2 conditions in a way that it evaluates to false when the inner breaked.

Alternatively set a breakOuter = FALSE before the first while, set breakOuter = True on the inner while s directly before you break and add and breakOuter == false to the outer while condition

Answer 2

I think that the simplest way is to just use

return 

instead of

break