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);

     }

 }