4.4 KiB
4.4 KiB
title | id | challengeType |
---|---|---|
Jaro distance | 5a23c84252665b21eecc7ec2 | 5 |
Description
- \(m\) is the number of matching characters;
- \(t\) is half the number of transpositions.
- \(m = 4\)
- \(|s_1| = 6\)
- \(|s_2| = 5\)
- \(t = 0\)
Instructions
Tests
tests:
- text: <code>jaro</code> should be a function.
testString: assert(typeof jaro=='function','<code>jaro</code> should be a function.');
- text: <code>jaro("MARTHA", "MARHTA")</code> should return a number.
testString: assert(typeof jaro('MARTHA', 'MARHTA')=='number','<code>jaro()</code> should return a number.');
- text: <code>jaro("MARTHA", "MARHTA")</code> should return <code>0.9444444444444445</code>.
testString: assert.equal(jaro('MARTHA', 'MARHTA'), 0.9444444444444445,'<code>jaro("MARTHA", "MARHTA")</code> should return <code>0.9444444444444445</code>.');
- text: <code>jaro("DIXON", "DICKSONX")</code> should return <code>0.7666666666666666</code>.
testString: assert.equal(jaro('DIXON', 'DICKSONX'), 0.7666666666666666,'<code>jaro("DIXON", "DICKSONX")</code> should return <code>0.7666666666666666</code>.');
- text: <code>jaro("JELLYFISH", "SMELLYFISH")</code> should return <code>0.8962962962962964</code>.
testString: assert.equal(jaro('JELLYFISH', 'SMELLYFISH'), 0.8962962962962964,'<code>jaro("JELLYFISH", "SMELLYFISH")</code> should return <code>0.8962962962962964</code>.');
- text: <code>jaro("HELLOS", "CHELLO")</code> should return <code>0.888888888888889</code>.
testString: assert.equal(jaro('HELLOS', 'CHELLO'), 0.888888888888889,'<code>jaro("HELLOS", "CHELLO")</code> should return <code>0.888888888888889</code>.');
- text: <code>jaro("ABCD", "BCDA")</code> should return <code>0.8333333333333334</code>.
testString: assert.equal(jaro('ABCD', 'BCDA'), 0.8333333333333334,'<code>jaro("ABCD", "BCDA")</code> should return <code>0.8333333333333334</code>.');
Challenge Seed
function jaro (s, t) {
// Good luck!
}
Solution
function jaro (s, t) {
var s_len = s.length;
var t_len = t.length;
if (s_len == 0 && t_len == 0) return 1;
var match_distance = Math.max(s_len, t_len) / 2 - 1;
var s_matches = new Array(s_len);
var t_matches = new Array(t_len);
var matches = 0;
var transpositions = 0;
for (var i = 0; i < s_len; i++) {
var start = Math.max(0, i - match_distance);
var end = Math.min(i + match_distance + 1, t_len);
for (var j = start; j < end; j++) {
if (t_matches[j]) continue;
if (s.charAt(i) != t.charAt(j)) continue;
s_matches[i] = true;
t_matches[j] = true;
matches++;
break;
}
}
if (matches == 0) return 0;
var k = 0;
for (var i = 0; i < s_len; i++) {
if (!s_matches[i]) continue;
while (!t_matches[k]) k++;
if (s.charAt(i) != t.charAt(k)) transpositions++;
k++;
}
return ((matches / s_len) +
(matches / t_len) +
((matches - transpositions / 2.0) / matches)) / 3.0;
}