hi..
how I can find the problems that based on grid and construct them, manipulate..
like these problems 
1- G.(A/B Matrix)->https://codeforces.net/contest/1360/problem/G
2-D.(Grid-00100)->https://codeforces.net/problemset/problem/1371/D
I solved them and I got AC..but I want more and more ..I cannot find it in tags of codeforces..
sorry for my bad English