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1428. Leftmost Column with at Least a One (Medium)

Related Topics

[Array] [Binary Search] [Matrix] [Interactive]

Hints

Hint 1

1. (Binary Search) For each row do a binary search to find the leftmost one on that row and update the answer.

Hint 2

2. (Optimal Approach) Imagine there is a pointer p(x, y) starting from top right corner. p can only move left or down. If the value at p is 0, move down. If the value at p is 1, move left. Try to figure out the correctness and time complexity of this algorithm.