Daniele Fucini
a6da9539cd
Added solutions of problems 81, 82 and 83 in C and python, and solution of problem 84 in C.
60 lines
1.6 KiB
Python
60 lines
1.6 KiB
Python
#!/usr/bin/python
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# In the 5 by 5 matrix below, the minimal path sum from the top left to the bottom right, by only moving to the right and down,
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# is indicated in bold red and is equal to 2427.
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#
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# *131* 673 234 103 18
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# *201* *96* *342* 965 150
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# 630 803 *746* *422* 111
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# 537 699 497 *121* 956
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# 805 732 524 *37* *331*
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#
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# Find the minimal path sum, in matrix.txt, a 31K text file containing a 80 by 80 matrix, from the top left to the bottom right
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# by only moving right and down.
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from timeit import default_timer
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def sum_paths(matrix, m, n):
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for i in range(m-2, -1, -1):
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matrix[m-1][i] = matrix[m-1][i] + matrix[m-1][i+1]
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matrix[i][m-1] = matrix[i][m-1] + matrix[i+1][m-1]
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for i in range(m-2, -1, -1):
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for j in range(n-2, -1, -1):
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if matrix[i][j+1] > matrix[i+1][j]:
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matrix[i][j] = matrix[i][j] + matrix[i+1][j]
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else:
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matrix[i][j] = matrix[i][j] + matrix[i][j+1]
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return matrix[0][0]
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def main():
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start = default_timer()
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try:
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fp = open('matrix.txt', 'r')
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except:
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print('Error while opening file {}'.format('matrix.txt'))
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exit(1)
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matrix = fp.readlines()
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fp.close()
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j = 0
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for i in matrix:
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matrix[j] = list(map(int, i.strip().split(',')))
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j = j + 1
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dist = sum_paths(matrix, 80, 80)
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end = default_timer()
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print('Project Euler, Problem 81')
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print('Answer: {}'.format(dist))
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print('Elapsed time: {:.9f} seconds'.format(end - start))
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if __name__ == '__main__':
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main()
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