8000 [Wildcard Matching] fix · Pull Request #49 · haoel/leetcode · GitHub
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[Wildcard Matching] fix #49

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Merged
merged 1 commit into from Feb 4, 2015
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[Wildcard Matching] fix #49

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53 changes: 27 additions & 26 deletions src/wildcardMatching/wildcardMatching.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -32,35 +32,31 @@ using namespace std;


bool isMatch(const char *s, const char *p) {

bool star = false;
const char *s1, *p1;
while( *s && (*p || star) ){
if (*p=='?' || *s == *p){
s++; p++;
}else if (*p=='*'){
//skip the "*", and mark a flag
star = true;
const char *last_s = NULL;
const char *last_p = NULL;
while (*s != '\0') {
// Here, '*' in the pattern is ungreedy. This means we are trying to
// build one or more one-character-to-one-character mappings between
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Buggy. * is treated as normal character when it meets *.

// the pattern string and the target string as much as possible.
if (*p == '*') {
last_s = s;
last_p = p++;
} else if (*p == '?' || *p == *s) {
s++;
p++;
//edge case
if (*p=='\0') return true;
//use s1 and p1 to store where the "*" match starts.
s1 = s;
p1 = p;
}else{
if (star==false) return false;
// if meet "*" previously, but the *s != *p
// reset the p, using '*' to match this situation
p = p1;
s = ++s1;
} else if (last_s) {
// Why not use stacks? Because '*' is ungreedy and it can match any
// character. If s becomes '\0' and the rest of p contains
// characters other than '*', that means:
// len(original_s) < len(original_p) - count(original_p, '*')
s = ++last_s;
p = last_p + 1;
} else {
return false;
}
}
//edge case: "s" is done, but "p" still have chars.
if (*s=='\0') {
while (*p=='*') p++; //filter all of '*'
if (*p=='\0') return true;
}
return false;
while (*p == '*') p++;
return *p == '\0';
}


Expand Down Expand Up @@ -89,6 +85,11 @@ int main(int argc, char** argv)
s = "a";
p = "a**";
cout << s << ", " << p << " : " << isMatch(s, p) << endl;

s = "*aa";
p = "*a";
cout << s << ", " << p << " : " << isMatch(s, p) << endl;

if (argc>2){
s = argv[1];
p = argv[2];
Expand Down
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