D - Index Trio

C - Just K

B - Make N

A - Trailing Zeros

Codeforces Round #697 (Div. 3) C. Ball in Berland

Codeforces Round #702 (Div. 3) E. Accidental Victory

Educational Codeforces Round 105 (Rated for Div. 2) B. Berland Crossword

April Fools Day Contest 2021 C. Fibonacci Words

G. 2^Sort

1139. Largest 1-Bordered Square

Given a 2D grid of 0s and 1s, return the number of elements in the largest square subgrid that has all 1s on its border, or 0 if such a subgrid doesn’t exist in the grid.