44 Wildcard Matching

Posted 2021-01-02 tobeabetterpig

44 Wildcard Matching


https://www.youtube.com/watch?v=3ZDZ-N0EPV0&t=423s


intialization: 
Empty string and empty pattern : true 
Empty string and “*” = true
Others false , since the initialized default value for the Boolean 2d array are false, so we 
Only need to change the true part 

Same as after two cases, else, we should return false, 
And since the default initialized value are false, and 
If the two cases didn’t turn it into true, and it should be 
Default value as false






Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5






class Solution {
    public boolean isMatch(String s, String p) {
     
      
      
      // replace multiple * with one * 
      // e.g. a**b***c --> a*b*c
      boolean met = false;
      StringBuilder sb = new StringBuilder();
      for(int i = 0; i < p.length(); i++){
        if(p.charAt(i) != ‘*‘){
          sb.append(p.charAt(i));
          met = false;
        }
        if(p.charAt(i) == ‘*‘ && met == false){
          sb.append(‘*‘);
          met = true;
        }else{
          continue;
        }
      }
      
      
      char[] str = s.toCharArray();
      char[] pattern = sb.toString().toCharArray();
      
      
      boolean T[][] = new boolean[str.length + 1][pattern.length + 1];
      
      if(pattern.length > 0 && pattern[0] == ‘*‘){
        T[0][1] = true;
      }
      
      T[0][0] = true;
      
      for(int i = 1; i < T.length; i++){
        for(int j = 1; j < T[0].length; j++){
          // why it‘s j-1, because the pattern starts from 0 index
          if(pattern[j-1] == str[i-1] || pattern[j-1] == ‘?‘){
            T[i][j] = T[i-1][j-1];
          }else if (pattern[j-1] == ‘*‘){
            T[i][j] = T[i-1][j] || T[j-1][i];
          }
        }
      }
      return T[str.length][pattern.length];
    }
}