def bad_shift_heuristic(t, w, n, m):
LAST = suffix.last_occurrence(w)
i = 1
while i <= n - m + 1:
j = m
while j > 0 and t[i + j - 1] == w[j]:
j = j - 1
if j == 0:
yield i
bad_character = LAST.get(t[i + j - 1], 0)
i = i + max(1, j - bad_character)
def quick_search(t, w, n, m):
LAST = suffix.last_occurrence(w)
i = 1
while i <= n - m + 1:
j = 1
while j <= m and t[i + j - 1] == w[j]:
j = j + 1
if j == m + 1:
yield i
bad_character = LAST.get(t[i + m], 0) if i + m <= n else 0
i = i + (m + 1 - bad_character)
def boyer_moore_bad_shift(t, w, n, m):
BM, LAST = suffix.boyer_moore_shift(w, m), suffix.last_occurrence(w[:-1])
i = 1
while i <= n - m + 1:
j = m
while j > 0 and t[i + j - 1] == w[j]:
j = j - 1
if j == 0:
yield i
bad_character = LAST.get(t[i + j - 1], 0)
i = i + max(BM[j], j - bad_character)
def horspool(t, w, n, m):
LAST = suffix.last_occurrence(w[:-1])
i = 1
while i <= n - m + 1:
c = t[i + m - 1]
if w[m] == c:
j = 1
while j < m and t[i + j - 1] == w[j]:
j = j + 1
if j == m:
yield i
bad_character = LAST.get(c, 0)
i = i + (m - bad_character)