(1+a1*t+(a1*t)^2+(a1*t)^3......(a1*t)^d) * (1+a2*t+(a2*t)^2...+(a2*t)^d) * ... * (1+an*t+(an*t)^2...(an*t)^d)`

same as 
****(a1*t-1)^-1*(a2*t-1)^-1*..*(an*t-1)^-1****

anyone knows how to get t^d coefficient,d<=1e18

I was thinking of FFT but its dlog(d) which will give tle ,any approach or article where I could read more about polynomial multiplication

Problem For the graphical solution what will be the time complexity ,number of edges in the graph

Question Not able to understand the editorial as well as not being able to move forward through my own approach. Let ai be represented as a*x+b*(x+1)=ai;then the diophentine solution be represented as x*(a0+k*(x+1))+(x+1)*(b0-k*x)=ai; so the total set broken down will be equal to K=a0+b0+k(K=sum of coefficients of x and (x+1) and we have to minimise K and sum over all ai. Not able to proceed further and also cant understand the editorial as well.