G面经prepare: Maximum Subsequence in Another String's Order

求string str1中含有string str2 order的 subsequence 的最小长度

DP做法：dp[i][j]定义为pattern对应到i位置，string对应到j位置时，shortest substring的长度，Int_Max表示不存在

package ShortestSubsequenceIncluding;

public class Solution {
    
      public String findShortest(String a, String b){
            if(a==null || b==null || a.length()==0 || b.length()==0) throw new IllegalArgumentException();

            int lena = a.length(), lenb = b.length();
            int[][] dp = new int[lenb][lena];

            for(int i=0; i<lenb; i++){
                char bc = b.charAt(i);
                for(int j=0; j<lena; j++){
                    char ac = a.charAt(j);
                    dp[i][j] = Integer.MAX_VALUE;

                    if(ac==bc){
                        if(i==0) dp[i][j] = 1;
                        else {
                            for (int t = 0; t < j; t++) {
                                if (dp[i - 1][t] == Integer.MAX_VALUE) continue;
                                else dp[i][j] = Math.min(dp[i][j], dp[i - 1][t] + j - t);
                            }
                        }
                    }
                }
            }

            int min = Integer.MAX_VALUE;
            int end = -1;

            for(int j=0; j<lena; j++){
                if(dp[lenb-1][j] < min) {
                    min = dp[lenb-1][j];
                    end = j;
                }
            }


            if(end==-1) return "no match!";
            return a.substring(end-min+1, end+1);
    }
    

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Solution sol =  new Solution();
        String res = sol.findShortest("acbacbc", "abc");
        System.out.println(res);

    }

}