冒泡排序

 for(int i =0;i<arr.length-1;i++) { for(int j=0;j<arr.length-i-1;j++) {//-1为了防止溢出 if(arr[j]>arr[j+1]) { int temp = arr[j]; arr[j]=arr[j+1]; arr[j+1]=temp; } } } }

二分查找法

给定数组是按从小到大排序好的

 //先排序 bubbleSort(arr); int left = 0; int right = arr.length - 1; int mid; while(left <= right){ mid = (left + right) % 2 == 0 ? (left + right) / 2 : (left + right) / 2 + 1; if(arr[mid] > val){ right = mid ; }else if (arr[mid] < val){ left = mid ; }else{ //找到该值 ** System.out.println(mid);** return; } } }

单链表反转

public class SingleLinkedList{ private static class Node{ private int val; private Node next; } //递归反转1-2-3-4 public Node reverse1(Node node){ if(node.next ==null || node== null){ return node; } Node temp= node.next; Node newNode = reverse1(node.next); node.next = null; temp.next = node; return newNode; } //遍历1-2-3-4 public Node reverse2(Node head){ Node prev = null; Node next = null; while (head != null){ next = head.next; head.next = prev; //在这里完成4->3->2->1 prev = head; head = next; } return prev; } }