## Editorial for An Animal Contest 2 P3 - Koala Balloons

Remember to use this editorial

**only**when stuck, and**not to copy-paste code from it**. Please be respectful to the problem author and editorialist.**Submitting an official solution before solving the problem yourself is a bannable offence.**Authors:

,#### Subtask 1

We iterate through each size and check if Sanjay can reach Sam with balloons. To do so, we use BFS and a 2 dimensional prefix sum array. To move to cell , we query the PSA to check that there are no obstacles in the square defined by . The maximum size is outputted.

**Time Complexity**:

#### Subtask 2

To optimize, we binary search the size .

**Time Complexity**:

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