Created
December 17, 2019 21:21
-
-
Save adamkorg/67f7f5bd9eb1c8ae73f1e55c1d54d1b9 to your computer and use it in GitHub Desktop.
Leetcode 10: Regular Expression Matching (recursive + memo)
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#include <iostream> | |
#include <string> | |
#include <vector> | |
using namespace std; | |
bool isMatch(string s, string p, int is, int ip, vector<vector<int>>& dp) { | |
if (dp[is][ip] != 0) return (dp[is][ip]==2); | |
int ois = is, oip = ip; //original is and ip values | |
while (is < s.size() && ip < p.size()) { | |
if (ip+1 < p.size() && p[ip+1] == '*') { | |
while (is < s.size()) { | |
if (p[ip] != '.' && s[is] != p[ip]) {dp[ois][oip]= (isMatch(s, p, is, ip+2, dp) ? 2 : 1); return dp[ois][oip]==2;} | |
if (isMatch(s, p, is, ip+2, dp)) {dp[ois][oip]=2; return true;} | |
is++; | |
} | |
ip += 2; | |
} | |
else if (p[ip] == '.') { is++; ip++; } | |
else { //match normal (non-wildcard) character | |
if (s[is] != p[ip]) {dp[ois][oip]=1; return false;} | |
else { is++; ip++; } | |
} | |
} | |
//trailing wildcards | |
if (is==s.size() && ip+1 < p.size() && p[ip+1]=='*') { | |
dp[ois][oip] = (isMatch(s, p, is, ip+2, dp) ? 2 : 1); | |
return (dp[ois][oip] == 2); | |
} | |
bool matched = (is == s.size() && ip == p.size()); | |
dp[ois][oip] = (matched ? 2 : 1); | |
return matched; | |
} | |
bool isMatch(string s, string p) { | |
vector<vector<int>> dp (s.size()+1, vector<int>(p.size()+1, 0)); //key[is,ip] values: 0=unvisited, 1=visited false return, 2=visited true return | |
return isMatch(s, p, 0, 0, dp); | |
} | |
int main() { | |
string s = "abcaaaaaaabaabcabac"; //"a"; //"ab"; //"aa"; //"mississippi";//"aab"; | |
string p = ".*ab.a.*a*a*.*b*b*"; //".*..a*"; //".*"; //"a*"; //"mis*is*p*.";//"c*a*b"; | |
cout << isMatch(s, p) << "\n"; | |
return 0; | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment