Coderbyte
Simple Mode
Have the function SimpleMode(arr) take the array of numbers stored in arr and return the number that appears most frequently (the mode). For example: if arr contains [10, 4, 5, 2, 4] the output should be 4. If there is more than one mode return the one that appeared in the array first (ie. [5, 10, 10, 6, 5] should return 5 because it appeared first). If there is no mode return -1. The array will not be empty.
function SimpleMode(arr) {
const count = {};
const firstOccurrence = {};
let maxCount = 0;
let mode = -1;
for (let i = 0; i < arr.length; i++) {
const num = arr[i];
if (num in count) {
count[num]++;
} else {
count[num] = 1;
firstOccurrence[num] = i;
}
if (count[num] > maxCount || (count[num] === maxCount && firstOccurrence[num] < firstOccurrence[mode])) {
maxCount = count[num];
mode = num;
}
}
return (maxCount > 1) ? mode : -1;
}
// keep this function call here
console.log(SimpleMode(readline()));
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