Re: [閒聊] 每日LeetCode

[Rushia (みけねこ的鼻屎)]

38. Count and Say
數數之後組成下一個字串，直接看例子：
https://assets.leetcode.com/uploads/2020/10/23/countandsay.jpg
n = 1: return 1 is the base case
n = 2: return count of last entry i.e. 1 1
n = 3: return count of last entry i.e. two 1's so 21
n = 4: we have one 2 and one 1 so 1211
n = 5: , we have one 1 and one 2 and two 1's so -> 111221
n = 6: we have three 1's, two 2's and one 1 so -> 312211
n = 7: we have one 3, one 1, two 2's and two 1's -> 13112221

思路：
1.每輪從第一個字往後數共有幾個連續數字。
2.把該輪從左到右把{數量}{數字}通通串接起來就是i+1的新字串。
3.從2跑到n執行 n - 1次

JavaCode：
class Solution {
    public String countAndSay(int n) {
        String str = "1";
        StringBuilder sb = new StringBuilder();
        for(int i = 2; i <= n; i++) {
            int j = 0, len = str.length();
            while (j < len) {
                char c = str.charAt(j);
                int count = 0, k = j;
                while (k < len && c == str.charAt(k++))  count++;
                sb.append(count).append(c);
                j += count;
            }
            str = sb.toString();
            sb.setLength(0);
        }
        return str;
    }
}


白癡閱讀測驗題目
花10分鐘看題目花三分鐘解題目= =
今天好忙 終於有時間可以打混偷寫LeetCode

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※ 編輯: Rushia (1.160.90.182 臺灣), 10/18/2022 16:40:34
推 JerryChungYC: 大師