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// Procedural
function task2a ( ns ) {
let ret = 0;
for ( const x of ns ) {
for ( const y of ns ) {
ret += Math.floor( x / y );
}
}
return ret;
}
// Functional, both using extracted code for Cartesian product.
const cartesian =
(...top_level_arrays) => top_level_arrays.reduce(
(accum, an_array) => accum.flatMap(
(element1) => an_array.map(
(element2) => [element1, element2].flat()
)));
// .map(), then sum via .reduce .
function task2b (ns) {
return cartesian(ns, ns)
.map(([x,y]) => Math.floor(x/y))
.reduce(((a,b) => a+b),0);
}
// Do the summing *and* mapping during the .reduce .
const task2c = (ns) => cartesian(ns, ns).reduce(((a,[x,y]) => a+Math.floor(x/y)),0);
let test_number = 0;
function is ( got, expected, desc ) {
test_number++;
const ok_msg = (got === expected) ? "ok" : "not ok";
const description = (typeof desc !== 'undefined') ? ` - ${desc}` : '';
console.log(`${ok_msg} ${test_number}${description}`);
}
const subs = [
[ 'task2a', task2a ],
[ 'task2b', task2b ],
[ 'task2c', task2c ],
];
const tests = [
[ 10, [2, 5, 9] , 'Example 1 from task'],
[ 49, [7,7,7,7,7,7,7], 'Example 2 from task'],
[ 10, [2, 5, 9] , 'Null array'],
];
for ( const [ sub_name, task2_coderef ] of subs ) {
for ( const [ expected, input, test_name ] of tests ) {
const got = task2_coderef(input);
is( got, expected, `${sub_name}: ${test_name}`);
}
}
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