in this Problem https://codeforces.net/contest/1829/problem/E

I Got a runTime Error because of this way of resizing my vector

grid.resize(n, vector(m));

but when I used this

grid = vector<vector>(n, vector(m));

it worked ?! What is the difference?

https://codeforces.net/contest/1829/submission/205458152 => Runtime Error

https://codeforces.net/contest/1829/submission/205697075 => Acc