动态规划——Freedom Trail

题目：https://leetcode.com/problems/freedom-trail/

额。。。不解释大意了，题目我也不想写过程了有点繁琐，直接给出代码：

 public int findRotateSteps(String ring, String key) {
         int rlen = ring.length();
         int klen = key.length();
         int[][]dp = new int[klen+1][rlen+1];
         int temp = 0,step = 0,diff = 0;
         for(int i = 0;i<=klen;i++) {
             for(int j = 1;j<=rlen;j++)
                 if(i==0)dp[i][j] = 0;
                 else dp[i][j] = Integer.MAX_VALUE;
         }
         for(int i = 1;i<=klen;i++) {
             for(int j = 1;j<=rlen;j++) {
                 temp = Integer.MAX_VALUE;
                 if(ring.charAt(j-1)==key.charAt(i-1)) {
                     if(i==1)temp = Math.min(j-1,rlen+1-j);
                     else {
                         for(int k = 1;k<=rlen;k++)
                             if(dp[i-1][k]!=Integer.MAX_VALUE) {
                                 diff = Math.abs(j-k);
                                 step = Math.min(diff,rlen-diff);
                                 temp = Math.min(temp,step+dp[i-1][k]);
                             }
                     }
                 }
                 dp[i][j] = temp;
             }
         }
         /*
         for(int i = 1;i<=klen;i++) {
             for(int j = 1;j<=rlen;j++)
                 System.out.print(dp[i][j]+" ");
             System.out.println();
         }*/
         int ans = dp[klen][1];
         for(int i = 2;i<=rlen;i++) {
             ans = ans < dp[klen][i]?ans:dp[klen][i];
         }
         return ans+klen;
     }