被 leetcode 上的靠前的答案震惊了

This topic created in 2738 days ago, the information mentioned may be changed or developed.

https://leetcode.com/problems/count-and-say/description/

好奇点开了排名第一的答案。。。。很多人也许见怪不怪了吧

高中搞 NOIP 的时候还想过，如果有题目不会做，我就直接把题目给的输入输出给直接输出，当然并没有去做。

class Solution: def countAndSay(self, n): """ :type n: int :rtype: str """ D = {1: '1', 2: '11', 3: '21', 4: '1211', 5: '111221', 6: '312211', 7: '13112221', 8: '1113213211', 9: '31131211131221', 10: '13211311123113112211', 11: '11131221133112132113212221', 12: '3113112221232112111312211312113211', 13: '1321132132111213122112311311222113111221131221', 14: '11131221131211131231121113112221121321132132211331222113112211', 15: '311311222113111231131112132112311321322112111312211312111322212311322113212221', 16: '132113213221133112132113311211131221121321131211132221123113112221131112311332111213211322211312113211', 17: '11131221131211132221232112111312212321123113112221121113122113111231133221121321132132211331121321231231121113122113322113111221131221', 18: '31131122211311123113321112131221123113112211121312211213211321322112311311222113311213212322211211131221131211132221232112111312111213111213211231131122212322211331222113112211', 19: 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27: 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30: 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return D[n]

Supplement 1 Nov 14, 2018

大家已经不是见怪不怪了，而是习以为常了。

个人觉得在 LeetCode 这个平台，更多的是研究解题思路，写出优雅的解法。

正文中的例子，虽然能通过测试，但不具有泛化性，可以说在生产过程中基本毫无用处，应该算是违背平台的初衷了吧。

leetcode

答案

字典

15 replies 2018-11-14 16:43:17 +08:00

huntzhan

Nov 13, 2018

leetcode 打表还行

24bit

Nov 13, 2018

习惯就好

midasplus

Nov 13, 2018

搞过 noip 应该知道骗分和打表呀(

vegito2002

Nov 13, 2018

leetcode contest 比赛的时候这种人多了去了, 见一个举报一个

xxx749

Nov 13, 2018 via Android

这题目什么意思，没看懂

nililnellaf

Nov 13, 2018

noip 骗分不奇怪啊手算也只能算个小数据

mmnsghgn

Nov 13, 2018

https://leetcode.com/problems/stone-game/description/

`return true`

yuikns

Nov 13, 2018 via iPhone

@xxx749 每一步都是上一步的描述

1
一个 1，即 11
二个 1，即 21
一个 2，一个 1，即 1211
... 以此类推

Xs0ul

Nov 14, 2018

@zengjian #7 我也看过这个，必胜策略就是比奇偶两列那个多，然后只取多的那个

xxx749

Nov 14, 2018 via Android

正则的性能这么差的吗？ JS 才 beats 15.11

yuikns

Nov 14, 2018

刚发现这道题我是做过的。
两年前是这么写的 (0ms)：

void i2v(int i, vector<int> & r) {
int offset = r.size() - 1;
while (i > 0) {
r.push_back(i % 10);
i /= 10;
}
for (int j = offset; j < (r.size() - offset) / 2; j++) {
int t = r[j];
r[j] = r[r.size() - 1 - j - offset];
r[r.size() - 1 - j - offset] = t;
}
}

vector<int> gen(vector<int> &c, int n) {
if (n > 0) {
vector<int> r;
int vv = c[0];
int vc = 0;
for (int i = 0; i < c.size(); i++) {
if (c[i] == vv) {
vc++;
} else {
i2v(vc,r);
r.push_back(vv);
vc = 1;
vv = c[i];
}
}
if (vc > 0) {
i2v(vc,r);
r.push_back(vv);
}
return gen(r, n - 1);
} else {
return c;
}
}

string countAndSay(int n) {
vector<int> c;
c.push_back(1);
vector<int> r = gen(c, n - 1);
char str[r.size() + 1];
str[r.size()] = '\0';
for (int i = 0; i < r.size(); i++) {
//s += (char)(r[i] + '0');
str[i] = r[i] + '0';
}
return string(str);
}

现在是这么写的 (4ms):

string countAndSay(int n) {
if(n <= 1) return "1";
string prev = countAndSay(n-1);
string buff = "";
char ci = '\0';
int cc = 0;
for(auto c : prev) {
if(c != ci) {
if(ci != '\0') {
buff += to_string(cc);
buff += ci;
}
ci = c;
cc = 1;
} else {
cc ++;
}
}
if (cc > 0) {
buff += to_string(cc);
buff += ci;
}
return buff;
}

越来越水了...

elikoi17

Nov 14, 2018 via Android

打表蒙点是正常操作吧。。。

echoZero

Nov 14, 2018

打表算是个正常的操作有时候
case 优先打表是可以过得

nyaruko

Nov 14, 2018

noip 确实有这么骗分的。中学参加过这类比赛的应该都熟悉。。

但是 leetcode 也这么玩。有点不好吧。毕竟是锻炼算法的地方

xmt328

Nov 14, 2018

打表也算是一个骗分的经典操作了