Largest range

# step 1: store all the values in hashmap
# step 2: iterate all the values in the array, for each value, check the range related to this value, how to check? check if the left/right number contains in the hashmap or not.
# if in the hashmap, set the value of that key in the hashmap to False(visited), then we don‘t need to recheck those False values
def largestRange(array):
    # Write your code here.
    bestRange = []
    longestLength = 0
    nums = {} # create a hashmap to store all the values, 
    
    for num in array:
        nums[num] = True # initialize all to True(all values do not have been touched at first
    for num in array:
        if not nums[num]:
            continue # if set to false, the value has been explored, do nothing
        nums[num] = False  # now, the current value is being explored
        currentLength = 1 # the currentLength is itself
        left = num - 1
        right = num + 1
        while left in nums:
            nums[left] = False
            currentLength += 1
            left -= 1 # continue to explore the range from right to left
        while right in nums:
            nums[right] = False
            currentLength += 1
            right += 1 # continue to expolre the range from left to right
            
        if currentLength > longestLength:
            longestLength = currentLength
            bestRange = [left + 1, right - 1] # at the end of the two while loops, right has been plus 1, left has been minus 1, need to restore the real values of left and right
    return bestRange