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[algorithms] 暴力算法（字符串匹配）

[algorithms] 暴力算法（字符串匹配）

 

 

 

 

一、代码

  1 #include <cstdio>
  2 #include <cstdlib>
  3 #include <cstring>
  4 
  5 
  6 int match1(char *source, char *pattern)
  7 {
  8     int debug = 0;
  9     int sl = strlen(source);
 10     int pl = strlen(pattern);
 11     printf("\n\n");
 12     printf("\t[match1_source_length]#\t%d\n", sl);
 13     printf("\t[match1_pattern_length]#\t%d\n", pl);
 14     //  mov: use for source moving
 15     int mov = 0;
 16     //  state: count matched char. if (state == pl) return index in source;
 17     int state = 0;
 18     //  index:  using for returning index if source match pattern
 19     int index = 0;
 20     for (int i=0; i<=sl-pl; i++) {
 21         //  index:  using for returning index if source match pattern
 22         mov = i;
 23         state = 0;
 24         index = i;
 25         for (int j=0; j<pl; j++, mov++) {
 26             if (source[mov] != pattern[j]) {
 27                 break;
 28             } else {
 29                 if (debug == 1) {
 30                     printf("\t[match1_test]#\t%c\n", source[mov]);
 31                 }
 32                 state += 1 ;
 33             }
 34             if(state==pl) {
 35                 printf("\t[match1]#\tindex[0, %d]\t:=\t%d\n", sl-pl, index);
 36                 return index;
 37             }
 38         }
 39     }
 40     printf("\t[match1]#\tnot match,\t%d\n", -1);
 41     return -1;
 42 }
 43 
 44 
 45 int match2(char *source, char *pattern)
 46 {
 47     int debug = 0;
 48     int sl = strlen(source);
 49     int pl = strlen(pattern);
 50     printf("\n\n");
 51     printf("\t[match2_source_length]#\t%d\n", sl);
 52     printf("\t[match2_pattern_length]#\t%d\n", pl);
 53     // index:  for return index;
 54     int index = 0; 
 55     // i,j:  control char moving in source or pattern.
 56     int i=0, j=0; 
 57     // state: count times for match pattern in source.
 58     int state = 0;
 59     while(i < sl  &&  j < pl)
 60     {
 61         /*
 62         if (source[i]==pattern[j]) {
 63             i++;
 64             j++;
 65             state++;
 66             if (debug == 1) {
 67                 printf("\t[match2_test]#\t%c\n", source[i-1]);
 68             }
 69         } else {
 70             index++;
 71             i = index;
 72             j = 0;
 73             state = 0;
 74             if (debug == 1) {
 75                 printf("\t[match2_index]#\t%d\n", index);
 76             }
 77         }
 78         if (state==pl) {
 79             printf("\t[match2]#\tindex[0, %d]\t:=\t%d\n", sl-pl, index);
 80             return index;    
 81         }
 82         */
 83         if (source[i] != pattern[j]) {
 84             if (debug == 1) {
 85                 printf("\t[not_match2_index]#\t%d\n", index);
 86                 printf("\t[not_match2_state]#\t%d\n", state);
 87             }
 88             index++;
 89             i = index;
 90             j = 0;
 91             state = 0;
 92         } else {
 93             if (debug == 1) {
 94                 printf("\t[match2_test]#\t%c\n", source[i]);
 95                 printf("\t[match2_index]#\t%d\n", index);
 96             }
 97             i++;
 98             j++;
 99             state++;
100             if (debug == 1) {
101                 printf("\t[match2_state]#\t%d\n", state);
102             }
103             if (state == pl) {
104                 printf("\t[match2]#\tindex[0, %d]\t:=\t%d\n", sl-pl, index);
105                 return index;    
106             }
107         }
108     }
109     
110     printf("\t[match2]#\tnot match,\t%d\n", -1);
111     return -1;
112 }
113 
114 
115 
116 void msg()
117 {
118     char s[] = "abchjhkhlhmhnhi";
119     char p[] = "hnhi";
120     match1(s,p);
121     match2(s,p);
122 }
123 
124 
125 int main(int argc, char *argv[], char *envp[])
126 {
127     msg();
128     
129     return 0;
130 }

 

 

 

 

二、运行结果

	[match1_source_length]#	15
	[match1_pattern_length]#	4
	[match1]#	index[0, 11]	:=	11


	[match2_source_length]#	15
	[match2_pattern_length]#	4
	[match2]#	index[0, 11]	:=	11

 

 

 

 

三、参考资料

 

　　1、　　cpp在线编译器　　　-　　https://coliru.stacked-crooked.com/

 

posted on 2024-11-20 00:34  lnlidawei  阅读(3)  评论(0)  编辑  收藏  举报