Skip to content

Commit 1fef7f4

Browse files
lxlxwlxlxw
committed
commit solution 15
1 parent a00c281 commit 1fef7f4

File tree

6 files changed

+117
-8
lines changed

6 files changed

+117
-8
lines changed

‎index-tags.md‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -8,6 +8,7 @@
88
| --- | --- | --- | --- | --- |
99
| [1](https://leetcode-cn.com/problems/two-sum) | [两数之和](/solution/1-99/0001.two-sum/) | `数组`,`哈希表` | <font color=green>简单</font> | ✅ |
1010
| [11](https://leetcode-cn.com/problems/container-with-most-water) | [盛最多水的容器](/solution/1-99/0011.container-with-most-water/) | `数组`,`双指针` | <font color=blue>中等</font> |✅ |
11+
| [15](https://leetcode-cn.com/problems/3sum) | [三数之和](/solution/1-99/0015.3sum/) | `数组`,`双指针` | <font color=blue>中等</font> |✅ |
1112
| [26](https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array) | [删除排序数组中的重复项](/solution/1-99/0026.remove-duplicates-from-sorted-array/) | `数组`,`双指针` | <font color=green>简单</font> |✅ |
1213
| [27](https://leetcode-cn.com/problems/remove-element) | [移除元素](/solution/1-99/0027.remove-element/) | `数组`,`双指针` | <font color=green>简单</font> |✅ |
1314
| [35](https://leetcode-cn.com/problems/search-insert-position) | [搜索插入位置](/solution/1-99/0035.search-insert-position/) | `数组`,`二分查找` | <font color=green>简单</font> |✅ |
@@ -67,6 +68,7 @@
6768
| 题号 | 题解 | 标签 | 难度 | 是否解题 |
6869
| --- | --- | --- | --- | --- |
6970
| [11](https://leetcode-cn.com/problems/container-with-most-water) | [盛最多水的容器](/solution/1-99/0011.container-with-most-water/) | `数组`,`双指针` | <font color=blue>中等</font> |✅ |
71+
| [15](https://leetcode-cn.com/problems/3sum) | [三数之和](/solution/1-99/0015.3sum/) | `数组`,`双指针` | <font color=blue>中等</font> |✅ |
7072
| [26](https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array) | [删除排序数组中的重复项](/solution/1-99/0026.remove-duplicates-from-sorted-array/) | `数组`,`双指针` | <font color=green>简单</font> |✅ |
7173
| [27](https://leetcode-cn.com/problems/remove-element) | [移除元素](/solution/1-99/0027.remove-element/) | `数组`,`双指针` | <font color=green>简单</font> |✅ |
7274
| [28](https://leetcode-cn.com/problems/implement-strstr) | [实现 strstr()](/solution/1-99/0028.implement-strstr%28%29/) | `双指针`,`字符串` | <font color=green>简单</font> |✅ |

‎index-type.md‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -412,7 +412,7 @@
412412
| [8](https://leetcode-cn.com/problems/string-to-integer-atoi) | [字符串转换整数 (atoi)](/solution/1-99/0008.string-to-integer-%28atoi%29/) | `数学`,`字符串` | <font color=blue>中等</font> |
413413
| [11](https://leetcode-cn.com/problems/container-with-most-water) | [盛最多水的容器](/solution/1-99/0011.container-with-most-water/) | `数组`,`双指针` | <font color=blue>中等</font> |✅ |
414414
| [12](https://leetcode-cn.com/problems/integer-to-roman) | [整数转罗马数字](/solution/1-99/0012.integer-to-roman/) | `数学`,`字符串` | <font color=blue>中等</font> |
415-
| [15](https://leetcode-cn.com/problems/3sum) | [三数之和](/solution/1-99/0015.3sum/) | `数组`,`双指针` | <font color=blue>中等</font> |
415+
| [15](https://leetcode-cn.com/problems/3sum) | [三数之和](/solution/1-99/0015.3sum/) | `数组`,`双指针` | <font color=blue>中等</font> |✅ |
416416
| [16](https://leetcode-cn.com/problems/3sum-closest) | [最接近的三数之和](/solution/1-99/0016.3sum-closest/) | `数组`,`双指针` | <font color=blue>中等</font> |
417417
| [17](https://leetcode-cn.com/problems/letter-combinations-of-a-phone-number) | [电话号码的字母组合](/solution/1-99/0017.letter-combinations-of-a-phone-number/) | `字符串`,`回溯算法` | <font color=blue>中等</font> |
418418
| [18](https://leetcode-cn.com/problems/4sum) | [四数之和](/solution/1-99/0018.4sum/) | `数组`,`哈希表`,`双指针` | <font color=blue>中等</font> |

‎solution/1-99/0015.3sum/README.md‎

Lines changed: 47 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,20 +1,61 @@
1-
# [15. xxx](https://leetcode-cn.com/problems/longest-common-prefix)
1+
# [15. 三数之和](https://leetcode-cn.com/problems/3sum/description/)
22

33
### 题目描述
44

5+
<p>给你一个包含 <em>n</em> 个整数的数组&nbsp;<code>nums</code>，判断&nbsp;<code>nums</code>&nbsp;中是否存在三个元素 <em>a，b，c ，</em>使得&nbsp;<em>a + b + c = </em>0 ？请你找出所有满足条件且不重复的三元组。</p>
56

7+
<p><strong>注意：</strong>答案中不可以包含重复的三元组。</p>
8+
9+
<p>&nbsp;</p>
10+
11+
<p><strong>示例：</strong></p>
12+
13+
<pre>给定数组 nums = [-1, 0, 1, 2, -1, -4]，
14+
15+
满足要求的三元组集合为：
16+
[
17+
[-1, 0, 1],
18+
[-1, -1, 2]
19+
]
20+
</pre>
621

722
### 解题思路
823

24+
![](http://lc-photo.xwlin.com/15.gif)
925

1026
### 具体解法
1127

12-
<!-- tabs:start -->
13-
1428
#### **Golang**
1529
```go
16-
30+
func threeSum(nums []int) [][]int {
31+
sort.Ints(nums)
32+
flagMap := make(map[string]bool)
33+
var res [][]int
34+
i := 0
35+
for i < len(nums) {
36+
if i-1 >= 0 && nums[i] == nums[i-1] {
37+
i++
38+
continue
39+
}
40+
p, q := 1, len(nums)-1
41+
for p+i < q {
42+
if nums[i]+nums[p+i]+nums[q] == 0 {
43+
flag := strconv.Itoa(nums[i]) + strconv.Itoa(nums[p+i]) + strconv.Itoa(nums[q])
44+
if _, ok := flagMap[flag]; !ok {
45+
res = append(res, []int{nums[i], nums[p+i], nums[q]})
46+
}
47+
flagMap[flag] = true
48+
p++
49+
q--
50+
} else if nums[i]+nums[p+i]+nums[q] > 0 {
51+
q--
52+
} else if nums[i]+nums[p+i]+nums[q] < 9 {
53+
p++
54+
}
55+
}
56+
i++
57+
}
58+
return res
59+
}
1760
```
1861

19-
<!-- tabs:end -->
20-

‎solution/1-99/0015.3sum/solution.go‎

Lines changed: 46 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,46 @@
1+
package leetcode
2+
3+
import (
4+
"sort"
5+
"strconv"
6+
)
7+
8+
/*
9+
* @lc app=leetcode.cn id=15 lang=golang
10+
*
11+
* [15] 三数之和
12+
*/
13+
14+
// @lc code=start
15+
func threeSum(nums []int) [][]int {
16+
sort.Ints(nums)
17+
flagMap := make(map[string]bool)
18+
var res [][]int
19+
i := 0
20+
for i < len(nums) {
21+
if i-1 >= 0 && nums[i] == nums[i-1] {
22+
i++
23+
continue
24+
}
25+
p, q := 1, len(nums)-1
26+
for p+i < q {
27+
if nums[i]+nums[p+i]+nums[q] == 0 {
28+
flag := strconv.Itoa(nums[i]) + strconv.Itoa(nums[p+i]) + strconv.Itoa(nums[q])
29+
if _, ok := flagMap[flag]; !ok {
30+
res = append(res, []int{nums[i], nums[p+i], nums[q]})
31+
}
32+
flagMap[flag] = true
33+
p++
34+
q--
35+
} else if nums[i]+nums[p+i]+nums[q] > 0 {
36+
q--
37+
} else if nums[i]+nums[p+i]+nums[q] < 9 {
38+
p++
39+
}
40+
}
41+
i++
42+
}
43+
return res
44+
}
45+
46+
// @lc code=end

‎solution/1-99/0015.3sum/solution_test.go‎

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,20 @@
1+
package leetcode
2+
3+
import (
4+
"testing"
5+
)
6+
7+
func TestThreeSum(t *testing.T) {
8+
var ret [][]int
9+
var nums []int
10+
11+
nums = []int{-1, 0, 1, 2, -1, -4}
12+
ret = [][]int{{-1, -1, 2}, {-1, 0, 1}}
13+
for k, num := range threeSum(nums) {
14+
for i, v := range num {
15+
if v != ret[k][i] {
16+
t.Fatalf("case fails %v\n", ret)
17+
}
18+
}
19+
}
20+
}

‎solution/1-99/_sidebar.md‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,7 @@
2020
- [12. 整数转罗马数字](solution/1-99/0012.integer-to-roman/)
2121
- [13. 罗马数字转整数 ✅](solution/1-99/0013.roman-to-integer/)
2222
- [14. 最长公共前缀](solution/1-99/0014.longest-common-prefix/)
23-
- [15. 三数之和](solution/1-99/0015.3sum/)
23+
- [15. 三数之和 ✅](solution/1-99/0015.3sum/)
2424
- [16. 最接近的三数之和](solution/1-99/0016.3sum-closest/)
2525
- [17. 电话号码的字母组合](solution/1-99/0017.letter-combinations-of-a-phone-number/)
2626
- [18. 四数之和](solution/1-99/0018.4sum/)

0 commit comments

Comments
 (0)