The Q4 shapes

Q4: one method, one grid, nine points. The recurring shapes:

Find-and-report-position — "return {row, col} of the largest value" as an int[]:

public int[] findMax(int[][] grid) {
    int[] at = new int[2];
    for (int r = 0; r < grid.length; r++) {
        for (int c = 0; c < grid[r].length; c++) {
            if (grid[r][c] > grid[at[0]][at[1]]) {
                at[0] = r;
                at[1] = c;
            }
        }
    }
    return at;
}

Seed from (0,0) — the precondition grid.length >= 1 makes it legal — and keep a strict > for the earliest tie.

Conditional transform — mutate cells matching a rule:

for (int r = 0; r < grid.length; r++) {
    for (int c = 0; c < grid[r].length; c++) {
        if (grid[r][c] < 0) {
            grid[r][c] = 0;
        }
    }
}

Count by neighborhood — the guarded-neighbor pattern (Module 8) inside a full-grid loop.

The Q4-specific discipline: when the answer is a POSITION, decide immediately how to encode it (int[2]? an int code like 10*r+c? a row-only?) — the prompt's return type forces one; misreading it is the classic zero.