当比对每个字串时
从右边开始匹配...#
<stdlib.h>#
<stdio.h>#
<
.h>/*Show usage*/
void usage(char * prog)
{
pr
f(\"Usage: %s text pattern\\n\", prog);exit(123);
}
/*Get
dist
for \'a\' to \'z\'*/void bm_dist(char * patt,
patt_length, * dist){
char ch;
k;for(ch = \'a\'; ch <= \'z\'; ch
) /*only \'a\' to \'z\' here*/dist[ch-97] = patt_length;
for(k = 0; k <= patt_length -1; k
)dist[patt[k] - 97] = patt_length - k - 1;
pr
f(\"dist: \");for(k = 0; k < 26; k
)pr
f(\"%d \", dist[k]);pr
f(\"\\n\");}
/*Algorithm*/
void bm_sm(char * patt, char * text,
patt_length, text_length, * dist){
i, j, k;i = patt_length - 1; /*Start from text[patt_length-1]*/
while(i < text_length)
{
j = patt_length - 1;
k = i;
while(j >= 0 && patt[j]
text[k]){
j --;
k --;
}
(j < 0){
pr
f(\"position %d\\n\", k + 1);pr
f(\"text: %s\\n\", text);pr
f(\"patn: \");for(j = 1; j <= k +1; j
)pr
f(\" \");pr
f(\"%s\\n\", patt);
;}
{
i = i + dist[text[i] - 97] - patt_length + j + 1;
}
}
pr
f(\"Not match!\\n\");}
( argc, char * argv)
{
char * text = NULL;
char * pattern = NULL;
dist[26];/*Check arguments*/
(argc != 3)usage(argv[0]);
{
text = argv[1];
pattern = argv[2];
}
pr
f(\"text: %s\\n\", text);pr
f(\"patn: %s\\n\", pattern);bm_dist(pattern, strlen(pattern), dist);
bm_sm(pattern, text, strlen(pattern), strlen(text), dist);
1;}
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