删除字符串回文串,回文字符组

package string.string1_5;public class Palindrome{ /** * 从两头向中间移动 * @param str * @return */ public static boolean isPalindrome(String str) { if(str == null || str.equals("")) return false ; int left = 0 ; int right = str.length()-1 ; while (left < right) { if(str.charAt(left++) != str.charAt(right--)) return false ; } return true ; } /** * 从中间向两头移动 * @param str * @return */ public static boolean isPalindrome2(String str) { if(str == null || str.equals("")) return false ; int left = str.length()/2 ; int right = str.length()-1-left ; while (left >= 0) { if(str.charAt(left--) != str.charAt(right++)) return false ; } return true ; } /** * 判断链表是否为回文 * @param node * @return */ public static boolean isPalindrome3(ListNode node) { //当链表为空或者链表只包含一个元素 if(node == null || node.next == null) return true ; ListNode head = new ListNode() ; head.next = node ; ListNode slow = head ; ListNode quick = head ; while (quick.next != null) { slow = slow.next ; for(int i=0 ; i<2 ; i++) if(quick.next != null) quick = quick.next ; else break ; } ListNode f = slow.next ; slow.next = null ; ListNode l = null ; ListNode t = null ; while (f != null) { t = f ; f = f.next ; t.next = l ; l = t ; } slow.next = t ; quick = slow.next ; slow = node ; while (quick != null) { if(slow.ch != quick.ch) return false ; slow = slow.next ; quick = quick.next ; } return true ; } public static void main(Stringwzdmf args) {/* ListNode node1 = new ListNode('a') ; ListNode node2 = new ListNode('b') ; ListNode node3 = new ListNode('c') ; ListNode node4 = new ListNode('c') ; ListNode node5 = new ListNode('b') ; ListNode node6 = new ListNode('a') ; node1.next = node2 ; node2.next = node3 ; node3.next = node4 ; node4.next = node5 ; node5.next = node6 ;*/ ListNode node1 = new ListNode('a') ; ListNode node2 = new ListNode('b') ; ListNode node3 = new ListNode('c') ; ListNode node5 = new ListNode('a') ; ListNode node6 = new ListNode('a') ; node1.next = node2 ; node2.next = node3 ; node3.next = node5 ; node5.next = node6 ; System.out.println(isPalindrome3(node1)); }}class ListNode{ char ch ; ListNode next ; public ListNode() {} public ListNode(char ch) { this.ch = ch; }}