检查两个索引之间的回文

function isPalindromeBetweenIndexes(str, startIndex, endIndex) {
    if (startIndex < 0 || endIndex >= str.length) {
        return false; // 索引无效
    }
    
    const substring = str.substring(startIndex, endIndex + 1);
    let left = 0;
    let right = substring.length - 1;
    
    while (left < right) {
        if (substring.charAt(left) !== substring.charAt(right)) {
            return false; // 不是回文
        }
        left++;
        right--;
    }
    
    return true; // 是回文
}

const inputString = "abcba";
const startIndex = 1;
const endIndex = 3;

const isPalindrome = isPalindromeBetweenIndexes(inputString, startIndex, endIndex);
console.log(isPalindrome); // 输出：true