Question

How to find the indexes of the first and last occurrences of an element in array in Node.js

Answer 1

function findFirstAndLastIndex(array, element) {
    let first = -1, last = -1;
    const size = array.length;
    
    for (let i = 0; i < size; i++) {
        if (array[i] != element) {
            continue;
        }
        
        if (first == -1) {
            first = i;
        }
        
        last = i;
    }
    
    if (first != -1) {
        console.log("First Occurrence = " + first);
        console.log("Last Occurrence = " + last);
    }
    else {
        console.log("Not Found");
    }
}
        
const array = [3, 2, 4, 7, 3, 0, 9, 8, 7, 6, 7, 7, 12, 18];
let element = 7;
        
findFirstAndLastIndex(array, element);




/*
run:

First Occurrence = 3
Last Occurrence = 11

*/

 

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