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
Dynamic programming approach. O(p*s*s) p is the length of patten, s is the length of string.
Time Limit Exceeded. I don’t think out better solution so far.
class Solution { public: bool isMatch(string s, string p) { //dp[i][j] stores whether patten[0~i] can match string[0~j - 1] dp[i][0] means whether patten[0~i] can match an empty string //dp[i][j] = dp[i - 1][k] && isMatch(p[i], s[k+1~j]), k = 0, 1, 2, ..., j , when k is j , s[k+1~j] means an empty string if(p.size() == 0 && s.size() == 0) return true; if(p.size() == 0) return false;//p.size() == 0 && s.size() > 0 bool dp[p.size()][s.size() + 1]; //memset(dp, false, sizeof(dp)); for(int i = 0; i < s.size() + 1; i++){ //initialize char patten = p[0]; dp[0][i] = isMatchChar(s.substr(0, i), patten); } for(int i = 1; i < p.size(); i++){ for(int j = 0; j < s.size() + 1; j++){ //populate the dp array for(int k = 0; k <= j; k++){ dp[i][j] = dp[i - 1][k] && isMatchChar(s.substr(k, j - k), p[i]); if(dp[i][j]){ break;// } } } } return dp[p.size() - 1][s.size()]; } bool isMatchChar(string s, char p){ if(p == '*') return true; if(p == '?' && s.size() == 1) return true; if(s.size() == 1 && p == s[0]) return true; return false; } };