Two Pointers 的 Tips:
- 双指针滑动窗口的经典写法。右指针不断往右移，移动到不能往右移动为止(具体条件根据题目而定)。当右指针到最右边以后，开始挪动左指针，释放窗口左边界。第 3 题，第 76 题，第 209 题，第 438 题，第 567 题，第 713 题，第 763 题，第 845 题，第 881 题，第 904 题，第 992 题，第 1004 题。
left, right := 0, -1
for left < len(s) {
if right+1 < len(s) && freq[s[right+1]-'a'] == 0 {
freq[s[right+1]-'a']++
right++
} else {
freq[s[left]-'a']--
left++
}
result = max(result, right-left+1)
}
- 快慢指针可以查找重复数字，时间复杂度 O(n)，第 287 题。
- 替换字母以后，相同字母能出现连续最长的长度。第 424 题。
- SUM 问题集。第 1 题，第 15 题，第 16 题，第 18 题，第 167 题，第 923 题。
| Title |
Solution |
Difficulty |
Time |
Space |
收藏 |
|
|
Medium |
O(n) |
O(1) |
❤️ |
|
|
Medium |
O(n) |
O(1) |
|
|
|
Medium |
O(n^2) |
O(n) |
❤️ |
|
|
Medium |
O(n^2) |
O(1) |
❤️ |
|
|
Medium |
O(n^3) |
O(n^2) |
❤️ |
|
|
Medium |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Hard |
O(n) |
O(n) |
❤️ |
|
|
Hard |
O(n) |
O(1) |
❤️ |
|
|
Medium |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(1) |
❤️ |
|
|
Hard |
O(n) |
O(n) |
❤️ |
|
|
Medium |
O(n) |
O(1 |
|
|
|
Medium |
O(n) |
O(1) |
❤️ |
|
|
Easy |
O(n) |
O(1) |
❤️ |
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
❤️ |
|
|
Medium |
O(n) |
O(1) |
❤️ |
|
|
Easy |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
❤️ |
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(n) |
|
|
|
Easy |
O(n) |
O(n) |
|
|
|
Medium |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(1) |
|
|
|
Easy |
O(n) |
O(n) |
|
|
|
Medium |
O(n) |
O(1) |
❤️ |
|
|
Medium |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(1) |
❤️ |
|
|
Medium |
O(n log n) |
O(n) |
|
|
|
Hard |
O(n) |
O(1) |
❤️ |
|
|
Medium |
O(n) |
O(n) |
|
|
|
Easy |
O(n) |
O(n) |
|
|
|
Medium |
O(n) |
O(1) |
|
|
|
Medium |
O(n log n) |
O(1) |
|
|
|
Medium |
O(n log n) |
O(1) |
|
|
|
Medium |
O(n^2) |
O(n) |
|
|
|
Easy |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(n) |
❤️ |
|
|
Easy |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(1) |
|
|
|
Hard |
O(n) |
O(n) |
❤️ |
|
|
Medium |
O(n) |
O(1) |
|
|
|
Medium |
O(n) |
O(1) |
|