Total number of paths between any two nodes - Graph vs. Complete Binary Tree
$begingroup$
In a graph, the total number of paths between any two nodes, is given by $n!$. Proof is in this link
In a Complete Binary tree, the total number of paths from root to leaf is basically, the number of leaves, which is $2^{log_2n - 1}$ and the time complexity of finding these is $O(n)$ since you would have to visit every node for doing so.
My question is, what is the time complexity of finding all paths between any two nodes in a complete binary tree ? Is it $2^n$ since from any node, you have two paths?
Cross posting from MathOverflow, as this is a more appropriate forum for the discussion in question.
graph-theory algorithms factorial computational-complexity trees
$endgroup$
add a comment |
$begingroup$
In a graph, the total number of paths between any two nodes, is given by $n!$. Proof is in this link
In a Complete Binary tree, the total number of paths from root to leaf is basically, the number of leaves, which is $2^{log_2n - 1}$ and the time complexity of finding these is $O(n)$ since you would have to visit every node for doing so.
My question is, what is the time complexity of finding all paths between any two nodes in a complete binary tree ? Is it $2^n$ since from any node, you have two paths?
Cross posting from MathOverflow, as this is a more appropriate forum for the discussion in question.
graph-theory algorithms factorial computational-complexity trees
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1
$begingroup$
I'm confused... in a tree, there is only ONE path between any two specified nodes.
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– Nick Peterson
Dec 3 '16 at 19:20
1
$begingroup$
And also, the claim about graphs is incorrect as stated. The number of paths between two nodes in a graph depends entirely on the structure of the graph -- it may be 0, it may be large. The largest it could ever be, however, is $(n-2)!$, in the complete graph.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:22
$begingroup$
@NickPeterson, your comment about the number of paths between two gives nodes, being (n-2)! is correct. I meant to say, the number of paths from any node to any other node is n!. Is that correct? About the tree, again, I mean the same thing. What is the total number of paths from root to any/(all) leaves? PS : Editing the question to remove ambiguity.
$endgroup$
– learningboy
Dec 3 '16 at 19:29
add a comment |
$begingroup$
In a graph, the total number of paths between any two nodes, is given by $n!$. Proof is in this link
In a Complete Binary tree, the total number of paths from root to leaf is basically, the number of leaves, which is $2^{log_2n - 1}$ and the time complexity of finding these is $O(n)$ since you would have to visit every node for doing so.
My question is, what is the time complexity of finding all paths between any two nodes in a complete binary tree ? Is it $2^n$ since from any node, you have two paths?
Cross posting from MathOverflow, as this is a more appropriate forum for the discussion in question.
graph-theory algorithms factorial computational-complexity trees
$endgroup$
In a graph, the total number of paths between any two nodes, is given by $n!$. Proof is in this link
In a Complete Binary tree, the total number of paths from root to leaf is basically, the number of leaves, which is $2^{log_2n - 1}$ and the time complexity of finding these is $O(n)$ since you would have to visit every node for doing so.
My question is, what is the time complexity of finding all paths between any two nodes in a complete binary tree ? Is it $2^n$ since from any node, you have two paths?
Cross posting from MathOverflow, as this is a more appropriate forum for the discussion in question.
graph-theory algorithms factorial computational-complexity trees
graph-theory algorithms factorial computational-complexity trees
edited Jan 26 '18 at 0:29
bof
51.5k558120
51.5k558120
asked Dec 3 '16 at 19:08
learningboylearningboy
285
285
1
$begingroup$
I'm confused... in a tree, there is only ONE path between any two specified nodes.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:20
1
$begingroup$
And also, the claim about graphs is incorrect as stated. The number of paths between two nodes in a graph depends entirely on the structure of the graph -- it may be 0, it may be large. The largest it could ever be, however, is $(n-2)!$, in the complete graph.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:22
$begingroup$
@NickPeterson, your comment about the number of paths between two gives nodes, being (n-2)! is correct. I meant to say, the number of paths from any node to any other node is n!. Is that correct? About the tree, again, I mean the same thing. What is the total number of paths from root to any/(all) leaves? PS : Editing the question to remove ambiguity.
$endgroup$
– learningboy
Dec 3 '16 at 19:29
add a comment |
1
$begingroup$
I'm confused... in a tree, there is only ONE path between any two specified nodes.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:20
1
$begingroup$
And also, the claim about graphs is incorrect as stated. The number of paths between two nodes in a graph depends entirely on the structure of the graph -- it may be 0, it may be large. The largest it could ever be, however, is $(n-2)!$, in the complete graph.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:22
$begingroup$
@NickPeterson, your comment about the number of paths between two gives nodes, being (n-2)! is correct. I meant to say, the number of paths from any node to any other node is n!. Is that correct? About the tree, again, I mean the same thing. What is the total number of paths from root to any/(all) leaves? PS : Editing the question to remove ambiguity.
$endgroup$
– learningboy
Dec 3 '16 at 19:29
1
1
$begingroup$
I'm confused... in a tree, there is only ONE path between any two specified nodes.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:20
$begingroup$
I'm confused... in a tree, there is only ONE path between any two specified nodes.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:20
1
1
$begingroup$
And also, the claim about graphs is incorrect as stated. The number of paths between two nodes in a graph depends entirely on the structure of the graph -- it may be 0, it may be large. The largest it could ever be, however, is $(n-2)!$, in the complete graph.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:22
$begingroup$
And also, the claim about graphs is incorrect as stated. The number of paths between two nodes in a graph depends entirely on the structure of the graph -- it may be 0, it may be large. The largest it could ever be, however, is $(n-2)!$, in the complete graph.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:22
$begingroup$
@NickPeterson, your comment about the number of paths between two gives nodes, being (n-2)! is correct. I meant to say, the number of paths from any node to any other node is n!. Is that correct? About the tree, again, I mean the same thing. What is the total number of paths from root to any/(all) leaves? PS : Editing the question to remove ambiguity.
$endgroup$
– learningboy
Dec 3 '16 at 19:29
$begingroup$
@NickPeterson, your comment about the number of paths between two gives nodes, being (n-2)! is correct. I meant to say, the number of paths from any node to any other node is n!. Is that correct? About the tree, again, I mean the same thing. What is the total number of paths from root to any/(all) leaves? PS : Editing the question to remove ambiguity.
$endgroup$
– learningboy
Dec 3 '16 at 19:29
add a comment |
1 Answer
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$begingroup$
From Wikipeida:
In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any acyclic connected graph is a tree. A forest is a disjoint union of trees.
I have no idea why you would want all paths between all nodes, but it would probably be bounded by at least $O(n^3)$, since you have $n(n-1)approx O(n^2)$ different nodes to choose from, and most depth-first search algorithms run in $O(n)$ time.
In short: $O(n)$ for finding the singular path between two nodes and $O(n^3)$ for finding all paths between any two nodes.
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$begingroup$
From Wikipeida:
In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any acyclic connected graph is a tree. A forest is a disjoint union of trees.
I have no idea why you would want all paths between all nodes, but it would probably be bounded by at least $O(n^3)$, since you have $n(n-1)approx O(n^2)$ different nodes to choose from, and most depth-first search algorithms run in $O(n)$ time.
In short: $O(n)$ for finding the singular path between two nodes and $O(n^3)$ for finding all paths between any two nodes.
$endgroup$
add a comment |
$begingroup$
From Wikipeida:
In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any acyclic connected graph is a tree. A forest is a disjoint union of trees.
I have no idea why you would want all paths between all nodes, but it would probably be bounded by at least $O(n^3)$, since you have $n(n-1)approx O(n^2)$ different nodes to choose from, and most depth-first search algorithms run in $O(n)$ time.
In short: $O(n)$ for finding the singular path between two nodes and $O(n^3)$ for finding all paths between any two nodes.
$endgroup$
add a comment |
$begingroup$
From Wikipeida:
In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any acyclic connected graph is a tree. A forest is a disjoint union of trees.
I have no idea why you would want all paths between all nodes, but it would probably be bounded by at least $O(n^3)$, since you have $n(n-1)approx O(n^2)$ different nodes to choose from, and most depth-first search algorithms run in $O(n)$ time.
In short: $O(n)$ for finding the singular path between two nodes and $O(n^3)$ for finding all paths between any two nodes.
$endgroup$
From Wikipeida:
In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any acyclic connected graph is a tree. A forest is a disjoint union of trees.
I have no idea why you would want all paths between all nodes, but it would probably be bounded by at least $O(n^3)$, since you have $n(n-1)approx O(n^2)$ different nodes to choose from, and most depth-first search algorithms run in $O(n)$ time.
In short: $O(n)$ for finding the singular path between two nodes and $O(n^3)$ for finding all paths between any two nodes.
answered Dec 3 '16 at 19:31
AlgorithmsXAlgorithmsX
4,1071828
4,1071828
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$begingroup$
I'm confused... in a tree, there is only ONE path between any two specified nodes.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:20
1
$begingroup$
And also, the claim about graphs is incorrect as stated. The number of paths between two nodes in a graph depends entirely on the structure of the graph -- it may be 0, it may be large. The largest it could ever be, however, is $(n-2)!$, in the complete graph.
$endgroup$
– Nick Peterson
Dec 3 '16 at 19:22
$begingroup$
@NickPeterson, your comment about the number of paths between two gives nodes, being (n-2)! is correct. I meant to say, the number of paths from any node to any other node is n!. Is that correct? About the tree, again, I mean the same thing. What is the total number of paths from root to any/(all) leaves? PS : Editing the question to remove ambiguity.
$endgroup$
– learningboy
Dec 3 '16 at 19:29