Thank you. So for the following code, which is used to get all the sub string with length k from a string: function fun1 ( str, k ) { let rtn = []; for ( let i = 0 ; i < str.length - k + 1 ; i++) { let current = str.substr(i, k); rtn.push(current) } return rtn; } the time complexity is O(n*k), which is approximated to O(n), right? I guess so. Thank you.

I find a tutorial online about this issue https://medium.com/netscape/authorization-with-casl-in-express-app-d94eb2e2b73b