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https://github.com/yuanyu90221/number-of-good-pairs
https://github.com/yuanyu90221/number-of-good-pairs
Last synced: 16 days ago
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- Host: GitHub
- URL: https://github.com/yuanyu90221/number-of-good-pairs
- Owner: yuanyu90221
- Created: 2020-08-09T10:14:05.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2020-08-09T10:22:25.000Z (over 4 years ago)
- Last Synced: 2024-04-21T14:00:52.848Z (9 months ago)
- Language: Go
- Size: 1.95 KB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# numbers-of-good-pairs
## 題目解讀：
### 題目來源:
[number-of-good-pairs](https://leetcode.com/problems/number-of-good-pairs/)
### 原文:
Given an array of integers nums.
A pair (i,j) is called good if nums[i] == nums[j] and i < j.
Return the number of good pairs.
### 解讀：
給定一個正整數陣列 nums
定義
(i, j)為good pair
如果i,j 符合
1 nums[i] === nums[j]
2 i < j
找出在 nums 中的所有good pair
## 初步解法:
### 初步觀察:
假設用一個 map儲存 每個值value出現的次數 e.g map[int]int
每個累計值 index後面的值 每多出一個相同值
則pair新增的值為上個 map[value]
因為後面的index剛好都可以跟前面出現過得值產生一個good pair
舉例來說：
[1, 1, 1, 1]
當i = 0 map[1] =1
count = 0
i = 1 map[1] = 2
count = count + 1(上一個 map[1]) = 1
i = 2 map[1] = 3
count = count + 2(上一個 map[1]) = 3
i = 3 map[1] = 4
count = count + 3(上一個 map[1]) = 6
### 初步設計:
given a integer array nums
set a integer result = 0
set valueMap = map[int]int
loop index i = 0 to i < length of nums:
check valueMap[nums[i]] exists or not
if valueMap[nums[i]] exists set result += valueMap[nums[i]]
valueMap[nums[i]]+=1
return result
## 遇到的困難
### golang map宣告不熟
由於不常使用golang map
因此花了些時間查訊golang map用法
### 題目上理解的問題
因為英文不是筆者母語
所以在題意解讀上 容易被英文用詞解讀給搞模糊
### pseudo code撰寫
一開始不習慣把pseudo code寫下來
因此 不太容易把自己的code做解析
### golang table driven test不熟
對於table driven test還不太熟析
所以對於寫test還是耗費不少時間
## 我的github source code
```golang
package num_identical
func numIdenticalPairs(nums []int) int {
ret := 0
valueMap := make(map[int]int)
for _, val := range nums {
if v, ok := valueMap[val]; ok == true {
ret += v
}
valueMap[val] += 1
}
return ret
}
```
## 測資的撰寫
```golang
package num_identical
import "testing"
func Test_numIdenticalPairs(t *testing.T) {
type args struct {
nums []int
}
tests := []struct {
name string
args args
want int
}{
{
name: "Example1",
args: args{
nums: []int{1, 2, 3, 1, 1, 3},
},
want: 4,
},
{
name: "Example2",
args: args{
nums: []int{1, 1, 1, 1},
},
want: 6,
},
{
name: "Example3",
args: args{
nums: []int{1, 2, 3},
},
want: 0,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := numIdenticalPairs(tt.args.nums); got != tt.want {
t.Errorf("numIdenticalPairs() = %v, want %v", got, tt.want)
}
})
}
}
```
## my self record
[leetcode iron 30 day 4th day](https://hackmd.io/L6PVb6phTiW5O1SBbcpPKQ?view)
## 參考文章
[golang test](https://ithelp.ithome.com.tw/articles/10204692)
[golang map宣告](https://michaelchen.tech/golang-programming/map/)