Eertree: Difference between revisions
Added D
m (→{{header|REXX}}: elided superfluous blank lines.) |
(Added D) |
||
Line 17:
* [https://arxiv.org/abs/1506.04862 Cornell University Library, Computer Science, Data Structures and Algorithms ───► EERTREE: An Efficient Data Structure for Processing Palindromes in Strings].
<br><br>
=={{header|D}}==
{{trans|Go}}
<lang D>import std.array;
import std.stdio;
void main() {
auto tree = eertree("eertree");
writeln(subPalindromes(tree));
}
struct Node {
int length;
int[char] edges;
int suffix;
}
const evenRoot = 0;
const oddRoot = 1;
Node[] eertree(string s) {
Node[] tree = [
Node(0, null, oddRoot),
Node(-1, null, oddRoot),
];
int suffix = oddRoot;
int n, k;
foreach (i, c; s) {
for (n=suffix; ; n=tree[n].suffix) {
k = tree[n].length;
int b = i-k-1;
if (b>=0 && s[b]==c) {
break;
}
}
if (c in tree[n].edges) {
suffix = tree[n].edges[c];
continue;
}
suffix = tree.length;
tree ~= Node(k+2);
tree[n].edges[c] = suffix;
if (tree[suffix].length == 1) {
tree[suffix].suffix = 0;
continue;
}
while (true) {
n = tree[n].suffix;
int b = i-tree[n].length-1;
if (b>=0 && s[b]==c) {
break;
}
}
tree[suffix].suffix = tree[n].edges[c];
}
return tree;
}
auto subPalindromes(Node[] tree) {
auto s = appender!(string[]);
void children(int n, string p) {
foreach (c, n; tree[n].edges) {
p = c ~ p ~ c;
s ~= p;
children(n, p);
}
}
children(0, "");
foreach (c, n; tree[1].edges) {
string ct = [c].idup;
s ~= ct;
children(n, ct);
}
return s.data;
}</lang>
{{out}}
<pre>["ee", "e", "r", "t", "rtr", "ertre", "eertree"]</pre>
=={{header|Go}}==
| |||