I need some advise on a better approach here.
Say i've 2 arrays to compare, array1 & array2 and i need to check if values in array 1 exists in array 2, in PHP, i can use "array\_diff" function which works every-time.

Be default, what i think of is to iterate through array1, and for each values of array1, compare that again array2, two iterations, this will be (n\*n) time complexity, see my code below.

How do i improve this algorithm/code. My goal is to check if a value the one array in in another array. How do i improve this code so it won't take this much time of comparing two arrays.

```
const array1 = ["j1", "ff2", "3hj", "4sss", "5gh", "6ss", "7aqw"];
const array2 = ["klp3", "jks32", "44sss", "3hj", "5gh", "6ss", "7aqw"];

for (let index1 of array1){
  for (let index2 of array2){
    if (index1 === index2){
      console.log("Exists.", "index 1 value: " + index1, "Index 2 value: " + index2)
    }
  } 
}

```

I need to improve time taken. Another time complexity that is not Quadratic.