cpp code:

long long strangeGrid(long long r,long long c) { long long result = 0;

if (r % 2 != 0) {
    result = (r - 1) * 5 + (c - 1) * 2;  
} 
else {
    result = (r - 2) * 5 + (c - 1) * 2 + 1;
}

return result;

}