JSFiddle - React, Tailwind, and code Playground

by Hristiyan Dodov

JavaScript

console.clear();

function trionchecker(arr, outcome) {
    var pr = null;
    var prsmaller = null;
    var pr2 = null;
    var pr2smaller = null;
    var istrion = true;

    for (var i = 0; i < arr.length; i++) {
        if (pr) {
            prsmaller = (pr < arr[i]);
        }

        if (pr2) {
            pr2smaller = (pr2 < pr);
        }

        pr2 = pr;
        pr = arr[i];

        if (prsmaller == pr2smaller && prsmaller !== null) {
            istrion = false;
        }
    }
    
    console.log(arr, "is trion:", istrion ? "yes" : "no", "should be", outcome);
}

trionchecker([10, 2, 20, 15, 16, -10, 100, 99, 101], "yes");
trionchecker([20, 10], "yes");
trionchecker([1], "yes");
trionchecker([1, 5, 1, 0, 3], "no");
trionchecker([-10, 10, -2, 11, -22], "yes");
trionchecker([1, 10], "yes");
trionchecker([4, 11, 7, 16, 17], "no");
trionchecker([2, 10, 20], "no");