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A pull request from cx #164

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Merged
merged 2 commits into from
Nov 18, 2022
Merged

A pull request from cx #164

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340c17c
The original code did not consider the exit condition when the statio…
cxlalala Apr 7, 2020
9155022
The code in 09_dynamic_programming/python/01_longest_common_subsequen…
cxlalala Apr 7, 2020
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31 changes: 19 additions & 12 deletions 08_greedy_algorithms/python/01_set_covering.py
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Original file line number Diff line number Diff line change
Expand Up @@ -10,16 +10,23 @@

final_stations = set()

while states_needed:
best_station = None
states_covered = set()
for station, states_for_station in stations.items():
covered = states_needed & states_for_station
if len(covered) > len(states_covered):
best_station = station
states_covered = covered
def my_set_covering(states_needed, stations):
final_stations = set()
#while states_needed is not None: 这个不对，Set()而不是None
while states_needed:
best_station = None
states_covered = set()
for station, states_for_station in stations.items():
covered = states_needed & states_for_station
if len(covered) > len(states_covered) and station not in final_stations:
best_station = station
states_covered = covered
if best_station is not None:
states_needed -= states_covered
final_stations.add(best_station)
stations.pop(best_station)
else:
return None
return final_stations

states_needed -= states_covered
final_stations.add(best_station)

print(final_stations)
print(my_set_covering(states_needed, stations))
19 changes: 13 additions & 6 deletions 09_dynamic_programming/python/01_longest_common_subsequence.py
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Original file line number Diff line number Diff line change
@@ -1,6 +1,13 @@
if word_a[i] == word_b[j]:
# The letters match.
cell[i][j] = cell[i-1][j-1] + 1
else:
# The letters don't match.
cell[i][j] = max(cell[i-1][j], cell[i][j-1])
dp_table_blue = ["b", "l", "u", "e"]
dp_table_clues = ["c", "l", "u", "e", "s"]
dp_table = [[0 for i in range(len(dp_table_blue))] for i in range(len(dp_table_clues))] # (5,4)
print(dp_table)

for i in range(0, len(dp_table_blue)):
for j in range(0, len(dp_table_clues)):
if dp_table_clues[j] == dp_table_blue[i]:
dp_table[j][i] = dp_table[j-1][i-1] + 1
else:
dp_table[j][i] = max(dp_table[j-1][i], dp_table[j][i-1])

print(dp_table)
11 changes: 11 additions & 0 deletions 09_dynamic_programming/python/02_longest_common_substring.py
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
dp_table_blue = ["b", "l", "u", "e"]
dp_table_clues = ["c", "l", "u", "e", "s"]
dp_table = [[0 for i in range(len(dp_table_blue))] for i in range(len(dp_table_clues))] # (5,4)
print(dp_table)

for i in range(0, len(dp_table_blue)):
for j in range(0, len(dp_table_clues)):
if dp_table_clues[j] == dp_table_blue[i]:
dp_table[i][j] = dp_table[i-1][i-1] + 1

print(dp_table)