1394-find-lucky-integer-in-an-array

DevGod

Elf Vtuber

Caution

DevGod needs to write an editorial for this problem!

js

/**
 * @param {number[]} arr
 * @return {number}
 */
var findLucky = function(arr) {
    return _.toPairs(
        _.countBy(arr)
    ).filter(
        (el)=>Number(el[0])==el[1]
    ).sort(
        (el)=>-el[1]
    )[0]?.[1] ?? -1
};