Calculate the maximum consecutive sum in a sequence of numbers, keeping track of the range producing the max. Fork of https://gist.github.com/hiddenist/6926596

max_consecutive_sum_idx.py

# Finds the maximum consecutive sum in a list of numbers.
# Returns a three-value tuple containing:
#   0: Starting index of the max sum
#   1: Ending index of the max sum
#   2: The maximum sum
def max_consecutive_sum_idx(values):
    if not values:
        return None
    
    maxval = None
    prev = (-1, -1)
    
    for cur in enumerate(values):
        i, v = cur
        pi, pv = prev
        
        if prev[1] > 0:
            cur = (pi, v + pv)
        
        if maxval is None or cur[1] > maxval[2]:
            maxval = (cur[0], i, cur[1])
        
        prev = cur
    
    return maxval