动态规划子数组系列一＞环绕字符串中唯一的子字符串

题目： 

 

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解析： 

 

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代码:  

 public int findSubstringInWraproundString(String ss) {int n =  ss.length();int[] dp = new int[n];char[] s = ss.toCharArray();for(int i = 0; i < n; i++) dp[i] = 1;for(int i = 1; i < n; i++){if(s[i - 1] + 1 == s[i] || (s[i - 1] == 'z' && s[i] == 'a'))dp[i] += dp[i-1];}//去重:把dp表中的字串重复的，只留最长的字串(hash表来建立映射关系)int[] hash = new int[26];for(int i = 0; i < n; i++)hash[s[i]-'a'] = Math.max(hash[s[i]-'a'], dp[i]);//返回int ret = 0;for(int x : hash)ret += x;return ret;}