Vista - Question on Performance

$t1=date;$a=@();$b=@();$c=@();$d=@();$s=0;$z=0
 
$base=[System.Collections.Generic.Dictionary``2];
$h= New-Object $base.MakeGenericType(([type] "int",[type] "int"))
 
gc C:\m4000.txt | % {$l=$_.Split();$a+=[int]$l[0];$b+=[int]$l[1];$c+=[int]$l[2];$d+=[int]$l[3]}
 
for($i=0;$i -lt 4000;$i++){for($j=0;$j -lt 4000;$j++){$h[$a[$i]+$b[$j]]+=1}}
for($i=0;$i -lt 4000;$i++){for($j=0;$j -lt 4000;$j++){$s+=$h[-$c[$i]-$d[$j]]}}
 
$t2=date; $t=$t2.Subtract($t1).TotalSeconds
 
"Answer=" + $s + ", Time=" +$t
 
Answer=0, Time=1050.703125 (seconds)

import time 
 
t = time.clock()
 
q,w,e,r,sch,h = [],[],[],[],0,{} 
f = open("C:/m4000.txt","rt")
 
for o in range(4000): 
    row = map(int, f.readline().split()) 
    q.append(row[0]) 
    w.append(row[1]) 
    e.append(row[2]) 
    r.append(row[3])
f.close()
 
for x in q: 
    for y in w: 
        if (x+y) in h: 
            h[x+y] += 1 
        else: 
            h[x+y] = 1
 
for x in e: 
    for y in r: 
        if -(x+y) in h: 
            sch += h[-(x+y)] 
 
q,w,e,r,h = None,None,None,None,None 
print sch 
print time.clock() - t,"secs"
 
>>> ================================ RESTART ================================
>>> 
0
42.0711987577 secs