Wildcard matching

Signed-off-by: begeekmyfriend <[email protected]>

010_regular_expression_matching/regular_expression.c

@@ -4,21 +4,21 @@
 #include <string.h>
 
 bool isMatch(char* s, char* p) {
-    if (*p=='\0') {
+    if (*p == '\0') {
         return *s == '\0';
     }
-    //p's length 1 is special case 
-    if (*(p+1) == '\0' || *(p+1) !='*' ) {
-        if (*s=='\0' || ( *p !='.' && *s != *p )) {
+    /* p's length 1 is special case */
+    if (*(p + 1) == '\0' || *(p + 1) != '*') {
+        if (*s == '\0' || ( *p != '.' && *s != *p)) {
             return false;
         } else {
-            return isMatch(s+1, p+1);
+            return isMatch(s + 1, p + 1);
         }
     }
     int len = strlen(s);
     int i = -1;
-    while (i < len && (i <0 || *p=='.' || *p==*(s+i)) ){
-        if (isMatch(s+i+1, p+2)) {
+    while (i < len && (i < 0 || *p == '.' || *p == *(s + i))) {
+        if (isMatch(s + i + 1, p + 2)) {
             return true;
         }
         i++;

044_wildcard_matching/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test wildcard_matching.c

044_wildcard_matching/wildcard_matching.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+static bool isMatch(char* s, char* p)
+{
+    char *last_s = NULL;
+    char *last_p = NULL;
+    while(*s != '\0') {
+        if (*p=='*'){
+            //skip the "*", and mark a flag
+            p++;
+            //edge case
+            if (*p=='\0') return true;
+            //use last_s and last_p to store where the "*" match starts.
+            last_s = s;
+            last_p = p;
+        } else if (*p=='?' || *s == *p) {
+            s++;
+            p++;
+        } else if (last_s != NULL) {
+            // check "last_s" to know whether meet "*" before
+            // if meet "*" previously, and the *s != *p
+            // reset the p, using '*' to match this situation
+            p = last_p;
+            s = ++last_s;
+        } else {
+            // *p is not wildcard char, 
+            // doesn't match *s, 
+            // there are no '*' wildcard matched before
+            return false;
+        }
+    }
+    //edge case: "s" is done, but "p" still have chars.
+    while (*p == '*') {
+        p++;
+    }
+    return *p == '\0';
+}
+
+int main(int argc, char **argv)
+{
+    if (argc != 3) {
+        fprintf(stderr, "Usage: ./test string pattern\n");
+        exit(-1);
+    }
+
+    printf("%s\n", isMatch(argv[1], argv[2]) ? "true" : "false");
+    return 0;
+}