字符串匹配算法 BF/KMP实现/栈、队列

来源：互联网发布：过滤器 angular在js 编辑：程序博客网时间：2024/05/17 03:36
import java.util.Collection;import java.util.Iterator;import java.util.LinkedList;import java.util.Queue;import java.util.Stack;public class test1 {public static void main(String[] args) {Stack<String> stack = new Stack<String>();Queue<String> queue = new LinkedList<String>();//Queue< String> queue2 = new LinkedList<String>();for (String string : "my dog has fleas".split(" ")) {stack.add(string);//stack.push(string);queue.add(string);}while (!stack.isEmpty()&&!queue.isEmpty()) {System.out.println("stack  :  "+stack.pop());System.out.println("queue  ：     "+queue.remove());}System.out.println();String a = "abafsdag";String b = "ag";BF(a, b);//BFchar [] aa = a.toCharArray();char [] bb = b.toCharArray();System.out.println(KMP_Index(aa, bb));}/** * KMP算法 *//**  * 获得字符串的next函数值  *   * @param t  *            字符串  * @return next函数值  */  public static int[] next(char[] t) {  int[] next = new int[t.length];  next[0] = -1;  int i = 0;  int j = -1;  while (i < t.length - 1) {  if (j == -1 || t[i] == t[j]) {  i++;  j++;  if (t[i] != t[j]) {  next[i] = j;  } else {  next[i] = next[j];  }  } else {  j = next[j];  }  }  return next;  }  /**  * KMP匹配字符串  *   * @param s  *            主串  * @param t  *            模式串  * @return 若匹配成功，返回下标，否则返回-1  */  public static int KMP_Index(char[] s, char[] t) {  int[] next = next(t);  int i = 0;  int j = 0;  while (i <= s.length - 1 && j <= t.length - 1) {  if (j == -1 || s[i] == t[j]) {  i++;  j++;  } else {  j = next[j];  }  }  if (j < t.length) {  return -1;  } else  return i - t.length; // 返回模式串在主串中的头下标  }  /** * BF算法匹配查找 * @param a * @param b */public static void BF(String a ,String b) {int m ,n ,flag=0;for (int i = 0; i < a.length() ;i++) {m=i;for (int k = 0; k < b.length();k++) {n=k;if (a.charAt(m)==b.charAt(n) && m < a.length() && n < b.length() && flag==0) {m++;n++;if (n==b.length()) {flag = 1;System.out.println("起始位置：   "+i);System.out.println("true");}}else {break;}}}if (flag==0) {System.out.println("没有重复的  ");}}}
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