华为机试20141103

1.给定一个字符串，按照字符与‘U’的差的绝对值大小升序排列

import java.util.Scanner;  public class Main{      public static void main(String[] args) {          Scanner input = new Scanner(System.in);          String inputString = input.nextLine();          System.out.println(sort(inputString));      }        public static String sort(String str){          char[] ch = str.toCharArray();          boolean flag = true;        for(int i = 0; i < ch.length-1; i++){              for(int j = 0; j < ch.length-1-i; j++){                  int m = ch[j] - 'U';                  if(m < 0)                      m = -m;                  int n = ch[j+1] - 'U';                  if(n < 0)                      n = -n;                  if(m > n){                      char temp = ch[j];                      ch[j] = ch[j+1];                      ch[j+1] = temp;                    flag = false;                  }              }              if(flag)                break;        }          return new String(ch);        }  }  

2.删除字符串中重复次数最少的字符，如abb-->bb aabb-->空串

import java.util.HashMap;import java.util.Map;import java.util.Scanner;import java.util.Set;import java.util.List;import java.util.ArrayList;public class RemoveDuplicateLeastChar{public static void main(String[] args) {Scanner input = new Scanner(System.in);String inputString = input.nextLine();System.out.println(remove(inputString));}public static String remove(String str){Map<Character, Integer> map = new HashMap<Character, Integer>();char [] ch = str.toCharArray();for(char c : ch){if(map.containsKey(c))map.put(c, map.get(c) + 1);elsemap.put(c, 1);}int least = 128;Set<Character> set = map.keySet();for(Character cha : set) {if(map.get(cha) < least)least = map.get(cha);}List<Character> list = new ArrayList<Character> ();for(Character cha : set) {if(map.get(cha) == least){for(int j = 0; j< ch.length; j++){if(ch[j] == cha)list.add(ch[j]);}}}StringBuffer sb = new StringBuffer();for(char c : ch){if(!list.contains(c))sb.append(c);}return sb.toString();}}

3.给出二叉树中和为某一值的所有路径

import java.util.Scanner;import java.util.ArrayList;/*binarytree:      10   5     12 4   7  */class Node{int data;        Node left;        Node right;}public class AllSumTreePath{private Node root;public void insert(int key){Node node = new Node();node.data = key;if(root == null)root = node;else{Node current = root;Node parent = null;while(true){parent = current;if(key <= current.data){current = current.left;if(current == null){parent.left = node;return;}}else{current = current.right;if(current == null){parent.right = node;return;}}}}}public static void main(String[] args) {AllSumTreePath tree = new AllSumTreePath();Scanner input = new Scanner(System.in);int sum = input.nextInt();Scanner input1 = new Scanner(System.in);String inputString = input1.nextLine();String [] strarray = inputString.split(",");for(String val : strarray){int data = Integer.parseInt(val);tree.insert(data);}// tree.insert(10);// tree.insert(5);// tree.insert(12);// tree.insert(4);// tree.insert(7);// int sum = 22;solution(tree.root, sum, new ArrayList<Integer>());}public static void solution(Node node, int sum, ArrayList<Integer> path){if (node == null)  return;  path.add(node.data);if(node.left == null && node.right == null) { int pathNum = 0;for(int value : path){pathNum = pathNum + value;}if(pathNum == sum){boolean isFirst = true;for(int value : path){if(isFirst){System.out.print(value);isFirst = false;}elseSystem.out.print("," + value);}System.out.println();}}solution(node.left, sum, path);  solution(node.right, sum, path);path.remove(path.size() - 1);}}