I have an assignment where I need to find the smallest number in an array using a recursive function. To be clear: I have been provided a working solution. I just for the life of me can't figure out why my own algorithm doesn't work.
function minimum(ns) {
if (ns.length === 1) {
return ns[0];
}
else {
const first = ns[0]
const second = ns[1]
if (first >= second) {
return minimum(ns.slice(1))
}
else {
return minimum(ns.splice(1,1))
}
}
}
minimum([0, 1]This code returns 1 instead of zero... My thinking goes as follows:
Why does this return 1 instead of 0?
Hope someone can help Kind regards!
Rather than Array.slice() and Array.splice, you can use destructuring assignment:
function minimum(ns)
{
if (ns.length === 1)
{
return ns[0];
}
const [first, second, ...tail] = ns;
if (first >= second)
{
return minimum([second, ...tail]);
} else {
return minimum([first, ...tail]);
}
}
or
function minimum(ns)
{
if (ns.length === 1) return ns[0];
const [first, second, ...tail] = ns;
return minimum([(first >= second?second:first), ...tail]);
}
console.log(minimum([1]));
console.log(minimum([3,1,2]));
console.log(minimum([3,2,2,3,4]));You need to splice outside of the call, because Array#splice returns the deleted elemenst of the array.
function minimum(ns) {
if (ns.length === 1) return ns[0];
const first = ns[0]
const second = ns[1]
if (first >= second) return minimum(ns.slice(1));
ns.splice(1, 1);
return minimum(ns);
}
console.log(minimum([0, 1]));
console.log(minimum([1, 0]));
console.log(minimum([5, 6, 3, 4, 7, 2, 1]));Mabe another approach would help better by separating the first element and take the rest of the array.
function minimum([first, ...ns]) {
if (ns.length === 0) return first;
if (first >= ns[0]) return minimum(ns);
return minimum([first, ...ns.slice(1)]);
}
console.log(minimum([0, 1]));
console.log(minimum([1, 0]));
console.log(minimum([5, 6, 3, 4, 7, 2, 1]));