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April 29, 2020 14:25
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Coin change problem in Python (Greedy and DP)
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def greedyCoinsChange(A, C): | |
C.sort(reverse = True) | |
counter = 0 | |
for c in C: | |
if (A > 0): | |
counter = counter + (A // c) | |
A = A % c | |
else: | |
break | |
return counter | |
import sys | |
INF = sys.maxsize | |
def dpCoinsChange(A, C): | |
C.sort(reverse = False) | |
rows = len(C) | |
cols = A + 1 | |
T = [[0 for j in range(cols)] for i in range(rows)] | |
for i in range(rows): | |
for j in range(1, cols): | |
if j < C[i]: | |
T[i][j] = T[i - 1][j] if i > 0 else INF | |
else: | |
T[i][j] = min(T[i - 1][j] if i > 0 else INF, 1 + T[i][j - C[i]]) | |
return T[rows - 1][cols - 1] | |
#*** 1 is required in C | |
A = 10 | |
C = [1, 5] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 10 | |
C = [1, 5, 10] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 4 | |
C = [1, 2, 3] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 5 | |
C = [1, 2] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 250 | |
C = list(range(1, 51)) | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 250 | |
C = [1, 5, 10, 25, 50] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 50 | |
C = list(range(1, 51)) | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 9 | |
C = [1, 2, 3, 5] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 30 | |
C = [1, 15, 25] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
A = 10 | |
C = [1, 2, 5, 3, 6] | |
print ("Greedy: %d\n DP: %d" % (greedyCoinsChange(A, C), dpCoinsChange(A, C))) | |
import timeit | |
greedyTime = """ | |
def greedyCoinsChange(A, C): | |
C.sort(reverse = True) | |
counter = 0 | |
for c in C: | |
if (A > 0): | |
counter = counter + (A // c) | |
A = A % c | |
else: | |
break | |
return counter | |
A = 12345 | |
C = list(range(1, 500)) | |
#A = 1000 | |
#C = list(range(1, 10000)) | |
greedyCoinsChange(A, C) | |
""" | |
dpTime = """ | |
import sys | |
INF = sys.maxsize | |
def dpCoinsChange(A, C): | |
C.sort(reverse = False) | |
rows = len(C) | |
cols = A + 1 | |
T = [[0 for j in range(cols)] for i in range(rows)] | |
for i in range(rows): | |
for j in range(1, cols): | |
if j < C[i]: | |
T[i][j] = T[i - 1][j] if i > 0 else INF | |
else: | |
T[i][j] = min(T[i - 1][j] if i > 0 else INF, 1 + T[i][j - C[i]]) | |
return T[rows - 1][cols - 1] | |
A = 12345 | |
C = list(range(1, 500)) | |
#A = 1000 | |
#C = list(range(1, 10000)) | |
dpCoinsChange(A, C) | |
""" | |
print ("Greedy: %f s\n DP: %f s" % (timeit.timeit(greedyTime, number = 1), timeit.timeit(dpTime, number = 1))) |
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