First Recurring Character
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// Google Question
// Given an array = [2,5,1,2,3,5,1,2,4];
// It should return 2
// Given an array = [2,1,1,2,3,5,1,2,4];
// It should return 1
// Given an array = [2,3,4,5];
// It should return undefiened
const firstRecurringCharacter = (array) => {
const map = new Map();
let first;
for (let i = 0; i < array.length; i++) {
let count = map.get(array[i]) | 1;
if (!map.get(array[i])) {
map.set(array[i], count);
} else {
if (!first) {
// At this point we know which is the first recurring character,
// so it doesn't matter if we add anything in first variable
// and we can use it to store the actual character
first = array[i];
break;
}
first = count + 1;
map.set(array[i], count + 1);
}
}
return first;
};
console.log(firstRecurringCharacter([2, 1, 1, 2, 3, 5, 1, 2, 4]));
console.log(firstRecurringCharacter([2, 5, 1, 2, 3, 5, 1, 2, 4]));
console.log(firstRecurringCharacter([2, 3, 4, 5]));
JavaScript
INFO