// your code goes here
function isPalindrome(str) {
// // return true if str is a palindrome else false
// let tmp = "";
// for(let i=str.length-1;i>=0;i--){
// tmp += str[i];
// }
// return tmp == str;
let left = 0, right = str.length - 1;
while(left < right){
if(str[left]!=str[right]) {
return false;
}
left++;
right--;
}
return true;
}
console.log(isPalindrome("racecar"))
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