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MatrixChianMultiplication.py
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34 lines (29 loc) · 1.09 KB
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import sys
def matrix_chain_order(p):
n = len(p) - 1 # Number of matrices in the chain
m = [[0] * (n + 1) for _ in range(n + 1)]
s = [[0] * (n + 1) for _ in range(n + 1)]
for length in range(2, n + 1):
for i in range(1, n - length + 2):
j = i + length - 1
m[i][j] = sys.maxsize
for k in range(i, j):
q = m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]
if q < m[i][j]:
m[i][j] = q
s[i][j] = k
return m, s
def print_optimal_parens(s, i, j):
if i == j:
print("A" + str(i), end="")
else:
print("(", end="")
print_optimal_parens(s, i, s[i][j])
print_optimal_parens(s, s[i][j] + 1, j)
print(")", end="")
# Example Usage
matrix_dimensions = [30, 35, 15, 5, 10, 20, 25]
m, s = matrix_chain_order(matrix_dimensions)
print("Minimum number of scalar multiplications:", m[1][len(matrix_dimensions) - 1])
print("Optimal Parenthesization: ", end="")
print_optimal_parens(s, 1, len(matrix_dimensions) - 1)