JSFiddle - React, Tailwind, and code Playground

HTML

<div id="result"></div>

JavaScript

function threeDistincts(items) {
        var distincts = 0, inArr = false;
        for (var i = 0; i < items[0].length; i++) {
            inArr = false;
            for (var j = 0; j < i; j++) {
                if (items[0][j] == items[0][i]) {
                    inArr = true;
                    break;
                }
            }
            if (!inArr) distincts++;
            if (distincts === 4) break;
        }
        items[0].length = items[1].length = i;
    }

var items = [[1,1,2,2,3,3,4,4,5,5],[0,0,0,1,0,1,0,1,0,1]];
threeDistincts(items);

document.getElementById('result').innerHTML = JSON.stringify(items);