LeetCode-Wildcard Matching

Implement wildcard pattern matching with support for

'?'

and

'*'

.

'?' Matches any single character.
'*' Matches any sequence of characters (including the empty sequence).

The matching should cover the entire input string (not partial).

The function prototype should be:
bool isMatch(const char *s, const char *p)

Some examples:
isMatch("aa","a") → false
isMatch("aa","aa") → true
isMatch("aaa","aa") → false
isMatch("aa", "*") → true
isMatch("aa", "a*") → true
isMatch("ab", "?*") → true
isMatch("aab", "c*a*b") → false

算法来自http://blog.unieagle.net/2012/11/07/leetcode%E9%A2%98%E7%9B%AE%EF%BC%9Awildcard-matching/

使用贪心法，首先按*将p串分割成各个不含*的子串，对于串头无*的子串必须从字符串头匹配，串尾无*的子串必须从字符串尾开始匹配，其他子串按顺序匹配即可

class Solution {
public:
vector<string> GenPattern(const char* p,bool& first,bool&last){
vector<string> ret;
if(p[0]=='\0')return ret;
string s="";
int i=0;
if(p[0]!='*')first=true;
while(p[i]!='\0'){
if(p[i]=='*'){
if(s!="")ret.push_back(s);
s.clear();
}
else{
s+=p[i];
}
i++;
if(p[i]=='\0'){
if(p[i-1]!='*'){
last=true;
ret.push_back(s);
}
}
}
return ret;
}
bool allStar(const char* p){
int i=0;
if(p[0]=='\0')return false;
while(p[i]!='\0'){
if(p[i]!='*')return false;
i++;
}
return true;
}
int kmpSearch(string& s,string& p,int start){
vector<int>next;
next.resize(p.length());
if(p.length()==1){
for(int i=start;i<s.length();i++)if(s[i]==p[0]||p[0]=='?')return i+1;
return -1;
}
next[0]=-1;
next[1]=0;
for(int i=2;i<p.length();i++){
int j=next[i-1];
while(j>=0&&p[j]!=p[i-1]&&p[j]!='?'&&p[i-1]!='?'){
j=next[j];
}
j++;
next[i]=j;
}
int ptr=0,i=start;
while(true){
if(s[i]==p[ptr]||p[ptr]=='?'){
ptr++;
i++;
if(ptr==p.length()){
return i;
}
if(i>=s.length())break;
}
else{
while(ptr>=0&&s[i]!=p[ptr]&&p[ptr]!='?'){
ptr=next[ptr];
}
ptr++;
i++;
if(i>=s.length())break;
}
}
return -1;
}
bool isMatch(const char *s, const char *p) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
bool first=false,last=false;
if(allStar(p))return true;
vector<string> ps=GenPattern(p,first,last);
string ss(s);
if(ps.size()==0){
if(ss.length()==0)return true;
else return false;
}
if(ps.size()==1){

if(first&&last){
if(ss.length()!=ps[0].length())return false;
for(int i=0;i<ss.length();i++){
if(ss[i]!=ps[0][i]&&ps[0][i]!='?')return false;
}
}
else if(first||last){
int k=0;
if(first){
int j=0;
for(int i=0;i<ps[0].length();i++){
if(j==ss.length())return false;
if(ss[j]!=ps[k][i]&&ps[k][i]!='?')return false;
j++;
}
}
if(last){
int i=ss.length()-1;
for(int j=ps[k].length()-1;j>=0;j--){
if(i<0)return false;
if(ss[i]!=ps[k][j]&&ps[k][j]!='?')return false;
i--;
}
}
}
else{
if(kmpSearch(ss,ps[0],0)<0)return false;
}
return true;
}
int k=0;
int end=0;
if(first){
int j=0;
for(int i=0;i<ps[0].length();i++){
if(j==ss.length())return false;
if(ss[j]!=ps[k][i]&&ps[k][i]!='?')return false;
j++;
}
k++;
end=ps[0].length();
}

for(;k<ps.size()-1;k++){
end=kmpSearch(ss,ps[k],end);
if(end==-1)return false;
}
if(last){
int i=ss.length()-1;
for(int j=ps[k].length()-1;j>=0;j--){
if(i<end)return false;
if(ss[i]!=ps[k][j]&&ps[k][j]!='?')return false;
i--;
}
}
else{
end=kmpSearch(ss,ps[k],end);
if(end==-1)return false;
}
return true;
}
};

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