Drawdown Duration

Problem

Compute the longest drawdown duration in a price series: the maximum number of consecutive observations strictly below the running peak. Any new high resets the counter.

Return 0 for an empty series or one that only makes new highs.

Hint

Duration counts time, not the depth of the drawdown.

Test cases

case 1

in: [[1,2,1,2,3]]

expected: 1

case 2

in: [[5,4,3,2,6]]

expected: 3

case 3

in: [[1,2,3]]

expected: 0

case 4

in: [[3,2,2,1,3]]

expected: 3

Starter codePython

def drawdown_duration(prices):
    # Your code here
    pass

4 test cases · run your code against them in the editor