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| # Calculates transitive closure of a relation | |
| # EECS 203 students: You are FORBIDDEN from using this code | |
| # for homework purposes. Only use this for self-learning | |
| # and testing. | |
| import strutils, sequtils, sugar, strformat | |
| type Matrix = seq[seq[bool]] | |
| func `$`(m: Matrix): string = | |
| for row in m: | |
| let zeroRow = row.map(x => (if x: 1 else: 0)) | |
| result.add(zeroRow.join(", ") & "\n") | |
| func toMatrix(m: seq[seq[int]]): Matrix = | |
| for row in m: | |
| let toBoolRow = row.mapIt(it == 1) | |
| result.add(toBoolRow) | |
| proc warshall(m: Matrix): void = | |
| var m = m # Shadow m, create var copy | |
| let n = high(m) # High(m) is the number of rows - 1 | |
| for k in 0..n: | |
| echo fmt"W[{k+1}] = " | |
| for i in 0..n: | |
| for j in 0..n: | |
| m[i][j] = m[i][j] or (m[i][k] and m[k][j]) | |
| echo m | |
| let x = @[ | |
| @[0, 0, 0, 0, 0], | |
| @[0, 0, 1, 0, 1], | |
| @[0, 0, 0, 0, 1], | |
| @[1, 0, 0, 0, 0], | |
| @[0, 1, 1, 0, 0], | |
| ].toMatrix() | |
| echo "Original Matrix" | |
| echo x | |
| warshall(x) |
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