public int minInsertions(String s) {

        StringBuffer sb = new StringBuffer(s);

        String b = sb.reverse().toString();

        return s.length() - lcs(s, b);

    }

    public int lcs(String str1, String str2) {

        int len1 = str1.length();

        int len2 = str2.length();

        int c[][] = new int[len1+1][len2+1];

        for (int i = 0; i <= len1; i++) {

            for( int j = 0; j <= len2; j++) {

                if(i == 0 || j == 0) {

                    c[i][j] = 0;

                } else if (str1.charAt(i-1) == str2.charAt(j-1)) {

                    c[i][j] = c[i-1][j-1] + 1;

                } else {

                    c[i][j] = Math.max(c[i - 1][j], c[i][j - 1]);

                }

            }

        }

        return c[len1][len2];

    }