weather

JavaScript/Levenshtein_distance/index.js

@@ -0,0 +1,36 @@
+/**
+ * @param {string} a 
+ * @param {string} b 
+ */
+module.exports.distance = function(a, b) {
+    aL = a.length;
+    bL = b.length;
+
+    if (aL == 0) return aL;
+    if (bL == 0) return bL;
+
+    let matrix = [];
+
+    for (let i = 0; i <= bL; i++) {
+        matrix[i] = [i];
+    }
+
+    for (let i = 0; i <= aL; i++) {
+        matrix[0][i] = i;
+    }
+
+    for (let i = 1; i <= bL; i++) {
+        for (let j = 1; j <= aL; j++) {
+            if (b.charAt(i-1) == a.charAt(j-1)) {
+                matrix[i][j] = matrix[i-1][j-1];
+            } else {
+                matrix[i][j] = Math.min(matrix[i-1][j-1] + 1,
+                               Math.min(matrix[ i ][j-1] + 1,
+                               matrix[i-1][j] + 1));
+            }
+        }
+    }
+
+    return matrix[bL][aL];
+}
+// we're doing the matrix implimentation https://en.wikipedia.org/wiki/Levenshtein_distance