java数据结构和算法------索引查找

  1 package iYou.neugle.search;
  2 
  3 import java.util.ArrayList;
  4 import java.util.List;
  5 
  6 public class Index_search {
  7     class IndexItem {
  8         public int index;
  9         public int start;
 10         public int length;
 11     }
 12 
 13     public int m = 100;
 14 
 15     public int[] table = new int[] { 101, 102, 103, 104, 105, 201, 202, 203,
 16             204, 301, 302, 303 };
 17 
 18     public List<IndexItem> indexTable = new ArrayList<Index_search.IndexItem>();
 19 
 20     public static void main(String[] args) {
 21         Index_search index = new Index_search();
 22         // 创建索引
 23         index.CreateIndex();
 24         // 向索引表中插入数据
 25         index.InsertIndex(205);
 26         // 利用索引表查找数据
 27         int result = index.SearchIndex(205);
 28         System.out.println("索引位置为" + result);
 29     }
 30 
 31     public void CreateIndex() {
 32         int[] type = new int[10000];
 33         int[] typeNum = new int[10000];
 34         for (int i = 0; i < this.table.length; i++) {
 35             int n = this.table[i] / m - 1;
 36             if (type[n] == 0) {
 37                 type[n] = 1;
 38             }
 39             typeNum[n]++;
 40         }
 41         int start = 0;
 42         for (int i = 0; i < typeNum.length; i++) {
 43             if (typeNum[i] == 0) {
 44                 break;
 45             }
 46             IndexItem item = new IndexItem();
 47             item.index = i;
 48             item.start = start;
 49             item.length = typeNum[i];
 50             indexTable.add(item);
 51             start += typeNum[i];
 52         }
 53     }
 54 
 55     public void InsertIndex(int key) {
 56         int n = key / m - 1;
 57         int index = -1;
 58         // 更新索引表
 59         for (int i = 0; i < this.indexTable.size(); i++) {
 60             if (n == this.indexTable.get(i).index) {
 61                 index = this.indexTable.get(i).start
 62                         + this.indexTable.get(i).length;
 63                 this.indexTable.get(i).length++;
 64                 break;
 65             }
 66         }
 67 
 68         for (int i = n + 1; i < this.indexTable.size(); i++) {
 69             this.indexTable.get(i).start++;
 70         }
 71 
 72         // 更新数组
 73         int[] temp = new int[this.table.length + 1];
 74         for (int i = 0; i < temp.length; i++) {
 75             if (i < index) {
 76                 temp[i] = this.table[i];
 77             } else if (i == index) {
 78                 temp[i] = key;
 79             } else {
 80                 temp[i] = this.table[i - 1];
 81             }
 82         }
 83 
 84         this.table = temp;
 85     }
 86 
 87     public int SearchIndex(int key) {
 88         int n = key / m - 1;
 89         int start = -1;
 90         int length = -1;
 91         // 找到索引位置
 92         for (int i = 0; i < this.indexTable.size(); i++) {
 93             if (n == this.indexTable.get(i).index) {
 94                 start = this.indexTable.get(i).start;
 95                 length = this.indexTable.get(i).length;
 96                 break;
 97             }
 98         }
 99 
100         if (start == -1) {
101             return -1;
102         }
103         // 从索引位置找数据
104         for (int i = start; i < start + length; i++) {
105             if (this.table[i] == key) {
106                 return i;
107             }
108         }
109         return -1;
110     }
111 }