twitterinterview.py

walls = [2,3,4,0,1,3,1,5,4,3,4,0,1,2,0,1,0,2,0,4]
lmax=0;
total=0;
copen=0;
buff=0;
print "\n-----------BEGIN ALG-----------\n"
if walls[0]>walls[1]:
    lmax=walls[0];
    copen=1;
for i in range(1, len(walls)):
    if walls[i]<walls[i-1]:
        copen=1;
        buff=buff+(lmax-walls[i]);
    else:
        if walls[i]<lmax:
            buff=buff+(lmax-walls[i]);
            buff=buff-(copen*(walls[i]-walls[i-1]));
            total=total+(copen*(walls[i]-walls[i-1]));
            copen=copen+1;
        else:
            total=total+buff;
            buff=0;
            copen=1;
            lmax=walls[i];
        
    print "step "+str(i)+": total = " +str(total) + " buff = " +str(buff);
print "\nTOTAL = "+str(total);
print "\n-----------END ALG-----------\n"

walls = [2,5,1,2,3,4,7,7,6] → 10
walls = [6,7,7,4,3,2,1,5,2] → 4

Another broken algorithm that depends on order.