Return the list of indices where an array is increasing for at least a particular number of values

import numpy as np
def monotonic_starts(arr, n):
    arr = np.asarray(arr)
    # 1: Find where arr is increasing
    increasing = np.diff(arr) > 0
    # 2: Pad with False to detect run boundaries at edges
    padded = np.concatenate([[False], increasing, [False]])
    # 3: Find run starts (+1) and ends (-1)
    edges = np.diff(padded.astype(int))
    starts = np.where(edges == 1)[0]
    ends = np.where(edges == -1)[0]
    # 4: Filter runs with at least (n-1) consecutive increases
    lengths = ends - starts
    return starts[lengths >= n - 1]