Data commit

Task/Symmetric-difference/JavaScript/symmetric-difference-1.js

@@ -0,0 +1,16 @@
+// in A but not in B
+function relative_complement(A, B) {
+    return A.filter(function(elem) {return B.indexOf(elem) == -1});
+}
+
+// in A or in B but not in both
+function symmetric_difference(A,B) {
+    return relative_complement(A,B).concat(relative_complement(B,A));
+}
+
+var a = ["John", "Serena", "Bob", "Mary", "Serena"].unique();
+var b = ["Jim", "Mary", "John", "Jim", "Bob"].unique();
+
+print(a);
+print(b);
+print(symmetric_difference(a,b));

Task/Symmetric-difference/JavaScript/symmetric-difference-2.js

@@ -0,0 +1,29 @@
+function Difference(A,B)
+{
+    var a = A.length, b = B.length, c = 0, C = [];
+    for (var i = 0; i < a; i++)
+     { var j = 0, k = 0;
+       while (j < b && B[j] !== A[i]) j++;
+       while (k < c && C[k] !== A[i]) k++;
+       if (j == b && k == c) C[c++] = A[i];
+     }
+    return C;
+}
+
+function SymmetricDifference(A,B)
+{
+    var D1 = Difference(A,B), D2 = Difference(B,A),
+        a = D1.length, b = D2.length;
+    for (var i = 0; i < b; i++) D1[a++] = D2[i];
+    return D1;
+}
+
+
+/* Example
+   A = ['John', 'Serena', 'Bob', 'Mary', 'Serena'];
+   B = ['Jim', 'Mary', 'John', 'Jim', 'Bob'];
+
+   Difference(A,B);           // 'Serena'
+   Difference(B,A);           // 'Jim'
+   SymmetricDifference(A,B);  // 'Serena','Jim'
+*/

Task/Symmetric-difference/JavaScript/symmetric-difference-3.js

@@ -0,0 +1,64 @@
+(() => {
+    'use strict';
+
+    const symmetricDifference = (xs, ys) =>
+        union(difference(xs, ys), difference(ys, xs));
+
+
+    // GENERIC FUNCTIONS ------------------------------------------------------
+
+    // First instance of x (if any) removed from xs
+    // delete_ :: Eq a => a -> [a] -> [a]
+    const delete_ = (x, xs) => {
+        const i = xs.indexOf(x);
+        return i !== -1 ? (xs.slice(0, i)
+            .concat(xs.slice(i, -1))) : xs;
+    };
+
+    //  (\\)  :: (Eq a) => [a] -> [a] -> [a]
+    const difference = (xs, ys) =>
+        ys.reduce((a, x) => filter(z => z !== x, a), xs);
+
+    // filter :: (a -> Bool) -> [a] -> [a]
+    const filter = (f, xs) => xs.filter(f);
+
+    // flip :: (a -> b -> c) -> b -> a -> c
+    const flip = f => (a, b) => f.apply(null, [b, a]);
+
+    // foldl :: (b -> a -> b) -> b -> [a] -> b
+    const foldl = (f, a, xs) => xs.reduce(f, a);
+
+    // nub :: [a] -> [a]
+    const nub = xs => {
+        const mht = unconsMay(xs);
+        return mht.nothing ? xs : (
+            ([h, t]) => [h].concat(nub(t.filter(s => s !== h)))
+        )(mht.just);
+    };
+
+    // show :: a -> String
+    const show = x => JSON.stringify(x, null, 2);
+
+    // unconsMay :: [a] -> Maybe (a, [a])
+    const unconsMay = xs => xs.length > 0 ? {
+        just: [xs[0], xs.slice(1)],
+        nothing: false
+    } : {
+        nothing: true
+    };
+
+    // union :: [a] -> [a] -> [a]
+    const union = (xs, ys) => {
+        const sx = nub(xs);
+        return sx.concat(foldl(flip(delete_), nub(ys), sx));
+    };
+
+    // TEST -------------------------------------------------------------------
+    const
+        a = ["John", "Serena", "Bob", "Mary", "Serena"],
+        b = ["Jim", "Mary", "John", "Jim", "Bob"];
+
+    return show(
+        symmetricDifference(a, b)
+    );
+})();

Task/Symmetric-difference/JavaScript/symmetric-difference-4.js

@@ -0,0 +1 @@
+["Serena", "Jim"]

Task/Symmetric-difference/JavaScript/symmetric-difference-5.js

@@ -0,0 +1,12 @@
+const symmetricDifference = (...args) => {
+    let result = new Set();
+    for (const x of args)
+        for (const e of new Set(x))
+            if (result.has(e)) result.delete(e)
+    		else result.add(e);
+
+    return [...result];
+}
+ // TEST -------------------------------------------------------------------
+console.log(symmetricDifference(["Jim", "Mary", "John", "Jim", "Bob"],["John", "Serena", "Bob", "Mary", "Serena"]));
+console.log(symmetricDifference([1, 2, 5], [2, 3, 5], [3, 4, 5]));

Task/Symmetric-difference/JavaScript/symmetric-difference-6.js

@@ -0,0 +1,2 @@
+["Jim", "Serena"]
+[1, 4, 5]