Use Thompson's algorithm to build the NFA for the following regular expression. Build the corresponding DFA and minimize it.
- ((ε|a)b)*
Line 16: | Line 16: | ||
<!-- ====================== START OF SOLUTION ====================== --> | <!-- ====================== START OF SOLUTION ====================== --> | ||
The non-deterministic finite automaton (NFA), built by applying Thompson's algorithm to the regular expression '''<nowiki>((ε|a)b)*</nowiki>''' is the following: | The non-deterministic finite automaton (NFA), built by applying Thompson's algorithm to the regular expression '''<nowiki>((ε|a)b)*</nowiki>''' is the following: | ||
− | < | + | <dot-hack> |
digraph nfa { | digraph nfa { | ||
{ node [shape=circle style=invis] start } | { node [shape=circle style=invis] start } | ||
Line 32: | Line 32: | ||
7 -> 1; 7 -> 8 | 7 -> 1; 7 -> 8 | ||
fontsize=10 | fontsize=10 | ||
− | |||
} | } | ||
− | </ | + | </dot-hack> |
Applying the determination algorithm to the above NFA, the following determination table is obtained: | Applying the determination algorithm to the above NFA, the following determination table is obtained: | ||
Line 90: | Line 89: | ||
! style="text-align: left; font-weight:normal; vertical-align: top; width: 50%;" |Graphically, the DFA is represented as follows: | ! style="text-align: left; font-weight:normal; vertical-align: top; width: 50%;" |Graphically, the DFA is represented as follows: | ||
− | < | + | <dot-hack> |
digraph dfa { | digraph dfa { | ||
{ node [shape=circle style=invis] start } | { node [shape=circle style=invis] start } | ||
Line 103: | Line 102: | ||
2 -> 2 [label="b"] | 2 -> 2 [label="b"] | ||
fontsize=10 | fontsize=10 | ||
− | |||
} | } | ||
− | </ | + | </dot-hack> |
Given the minimization tree to the right, the final minimal DFA is: | Given the minimization tree to the right, the final minimal DFA is: | ||
− | < | + | <dot-hack> |
digraph dfamin { | digraph dfamin { | ||
{ node [shape=circle style=invis] start } | { node [shape=circle style=invis] start } | ||
Line 119: | Line 117: | ||
1 -> 02 [label="b"] | 1 -> 02 [label="b"] | ||
fontsize=10 | fontsize=10 | ||
− | |||
} | } | ||
− | </ | + | </dot-hack> |
! style="text-align: left; font-weight:normal; vertical-align: top; width: 50%;" | The minimization tree is as follows. | ! style="text-align: left; font-weight:normal; vertical-align: top; width: 50%;" | The minimization tree is as follows. | ||
− | < | + | <dot-hack> |
digraph mintree { | digraph mintree { | ||
node [shape=none,fixedsize=true,width=0.2,fontsize=10] | node [shape=none,fixedsize=true,width=0.2,fontsize=10] | ||
Line 132: | Line 129: | ||
"{0, 2}" -> "{0,2} " [label=" a,b",fontsize=10] | "{0, 2}" -> "{0,2} " [label=" a,b",fontsize=10] | ||
fontsize=10 | fontsize=10 | ||
− | |||
} | } | ||
− | </ | + | </dot-hack> |
|} | |} | ||
<!-- ====================== END OF SOLUTION ====================== --> | <!-- ====================== END OF SOLUTION ====================== --> |
Problem
Use Thompson's algorithm to build the NFA for the following regular expression. Build the corresponding DFA and minimize it.
Solution
The non-deterministic finite automaton (NFA), built by applying Thompson's algorithm to the regular expression ((ε|a)b)* is the following:
Applying the determination algorithm to the above NFA, the following determination table is obtained:
In | α∈Σ | move(In, α) | ε-closure(move(In, α)) | In+1 = ε-closure(move(In, α)) |
---|---|---|---|---|
- | - | 0 | 0, 1, 2, 3, 4, 6, 8 | 0 |
0 | a | 5 | 5, 6 | 1 |
0 | b | 7 | 1, 2, 3, 4, 6, 7, 8 | 2 |
1 | a | - | - | - |
1 | b | 7 | 1, 2, 3, 4, 6, 7, 8 | 2 |
2 | a | 5 | 5, 6 | 1 |
2 | b | 7 | 1, 2, 3, 4, 6, 7, 8 | 2 |
Graphically, the DFA is represented as follows:
Given the minimization tree to the right, the final minimal DFA is: |
The minimization tree is as follows. |
---|