very weird raggedness word-wrap implementation written in Python

raggedness.py

# -*- coding: utf-8 -*-
from sys import argv, exit

cac = []
res = []
words = []
M = 0

for x in range(1000):
    cac.append([-1 for j in range(1000)])
    res.append(['' for j in range(1000)])

print 'start'

# 0, 45
def go(a, b):
    if cac[a][b] >= 0:
        return cac[a][b]
    if a == b:
        return 0

    csum = -1
    i = a
    while i < b:
        csum += len(words[i]) + 1
        i += 1

    if csum <= M or a == (b - 1):
        i = a
        while i < b:
            res[a][b] += words[i]
            i += 1
        cac[a][b] = (M - csum) ** 2
        return cac[a][b]

    ret = 10000000
    best_sp = -1
    sp = a + 1
    while sp < b:
        cur = go(a, sp) + go(sp, b)
        if cur <= ret:
            ret = cur
            best_sp = sp
        sp += 1

    res[a][b] = '{0}\n{1}'.format(res[a][best_sp], res[best_sp][b])
    cac[a][b] = ret
    return cac[a][b]

def main():
    global cac, res, words, M

    M = int(argv[1]) * 2
    text = argv[2]

    for word in text:
        words.append(word)

    size = len(words)
    go(0, size)
    print res[0][size]

if __name__ == '__main__':
    main()