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;
    }