https://leetcode.cn/problems/shortest-palindrome/submissions/591347819/
竟然是KMP题，没想到
真妙
```js
const generateNext = (str) => {
const arr = [-1];
let j = -1;
for (let i = 1; i < str.length; i++) {
const char = str;
while (j >= 0 && char != str) {
j = arr;
}
if (char == str) {
j++;
}
arr = j;
}
return arr;
};
const shortestPalindrome = (s) => {
const rev_s = s.split("").reverse().join("");
const next = generateNext(s + "#" + rev_s);
return rev_s+s.substring(next.pop()+1)
};
```
https://leetcode.cn/problems/transpose-file/submissions/591347880/
gpt过了，我操
```js
#!/bin/bash
input_file="file.txt"
awk '
{
for (i=1; i<=NF; i++){
a = $i
}
}
NF>p { p = NF }
END {
for(j=1; j<=p; j++) {
str=a
for(i=2; i<=NR; i++){
str=str" "a
}
print str
}
}' $input_file
```
https://leetcode.cn/problems/word-frequency/submissions/591347896/
又试了一下
gpt精准度真的不错...
```js
tr -s ' ' '\n' < words.txt | sort | uniq -c | sort -nr | awk '{print $2, $1}'
```
https://leetcode.cn/problems/compare-version-numbers/submissions/591524367/
简单题，k了
```js
var compareVersion = function(version1, version2) {
version1=version1.split('.').map((item)=>parseInt(item))
version2=version2.split('.').map((item)=>parseInt(item))
for (let index = 0; index < Math.max(version1.length,version2.length); index++) {
const num1 = version1??0;
const num2 = version2??0;
if(num1<num2){
return -1
}
if(num1>num2){
return 1
}
}
return 0
};
```
https://leetcode.cn/problems/combination-sum-iii/submissions/591526048/
回溯题，不想用位运算计算
```js
var combinationSum3 = function (k, n) {
const ban = new Array(10).fill(false);
const ans = [];
const dfs = (times, total, pos) => {
if (times == 0 && total == 0) {
const list = ban
.map((val, index) => {
if (val) {
return index;
} else {
return -1;
}
})
.filter((item) => item !== -1);
ans.push(list);
return;
}
if (times == 0) {
return;
}
if (total == 0) {
return;
}
for (let index = pos; index < 10; index++) {
if (!ban) {
ban = true;
dfs(times - 1, total - index, index + 1);
ban = false;
}
}
};
dfs(k, n, (pos = 1));
return ans;
};
```
https://leetcode.cn/problems/number-of-changing-keys/submissions/591570953/
打卡题，今天懒得做了
```js
var countKeyChanges = function(s) {
s= s.toLowerCase();
let ans=0
for (let index = 0; index < s.length-1; index++) {
ans+=s==s?0:1
}
return ans
};
```
https://leetcode.cn/problems/count-substrings-that-can-be-rearranged-to-contain-a-string-i/
讲道理，题目写的太抽象了
```js
var validSubstringCount = function (word1, word2) {
let list = new Array(26).fill(0);
for (const word of word2) {
list++;
}
let less = 0;
for (const value of list) {
if (value !== 0) {
less++;
}
}
let left = 0;
letans=0
for (let index = 0; index < word1.length; index++) {
const word = word1.charCodeAt() - 97;
list--;
if (list == 0) {
less--;
}
while (less == 0) {
const outChar = word1.charCodeAt() - 97;
left++;
if (list == 0) {
less++;
}
list++;
}
ans+=left
}
return ans
};
```
https://leetcode.cn/submissions/detail/592007875/
一样的题
```js
var validSubstringCount = function (word1, word2) {
let list = new Array(26).fill(0);
for (const word of word2) {
list++;
}
let less = 0;
for (const value of list) {
if (value !== 0) {
less++;
}
}
let left = 0;
letans=0
for (let index = 0; index < word1.length; index++) {
const word = word1.charCodeAt() - 97;
list--;
if (list == 0) {
less--;
}
while (less == 0) {
const outChar = word1.charCodeAt() - 97;
left++;
if (list == 0) {
less++;
}
list++;
}
ans+=left
}
return ans
};
```
https://leetcode.cn/problems/find-the-key-of-the-numbers/submissions/592403977/
简单题，打个卡
```js
var generateKey = function (num1, num2, num3) {
const generate = (num) => {
num = num + "";
while (num.length < 4) {
num = "0" + num;
}
return num;
};
num1 = generate(num1);
num2 = generate(num2);
num3 = generate(num3);
let ans = "";
for (let index = 0; index < 4; index++) {
const char1 = parseInt(num1);
const char2 = parseInt(num2);
const char3 = parseInt(num3);
ans=ans+Math.min(char1,char2,char3)
}
return parseInt(ans)
};
```
https://leetcode.cn/problems/sort-an-array/submissions/592498000/
快排竟然没过去
归并过了...
```js
var sortArray = function (nums) {
const mergeSort = (l, r) => {
if (l == r) {
return ];
}
const center = l + Math.floor((r - l) / 2);
const arr1 = mergeSort(l, center);
const arr2 = mergeSort(center + 1, r);
return merge(arr1, arr2);
};
const merge = (arr1, arr2) => {
const result = [];
let p1 = 0;
let p2 = 0;
while (p1 < arr1.length && p2 < arr2.length) {
if (arr1 <= arr2) {
result.push(arr1);
} else {
result.push(arr2);
}
}
while (p1 < arr1.length) {
result.push(arr1);
}
while (p2 < arr2.length) {
result.push(arr2);
}
returnresult
};
return mergeSort(0,nums.length-1)
};
```