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https://github.com/yuanyu90221/maximum-product-of-two-elements-in-an-array
https://github.com/yuanyu90221/maximum-product-of-two-elements-in-an-array
Last synced: 16 days ago
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- Host: GitHub
- URL: https://github.com/yuanyu90221/maximum-product-of-two-elements-in-an-array
- Owner: yuanyu90221
- Created: 2020-08-23T17:01:55.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2020-08-23T17:02:22.000Z (over 4 years ago)
- Last Synced: 2024-04-21T14:00:39.091Z (9 months ago)
- Language: Go
- Size: 1.95 KB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# maximum-product-of-two-elements-in-an-array
## 題目解讀：
### 題目來源:
[maximum-product-of-two-elements-in-an-array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array/)
### 原文:
Given the array of integers nums, you will choose two different indices i and j of that array. Return the maximum value of (nums[i]-1)*(nums[j]-1).
### 解讀：
給定一個正整數陣列nums, 任意選兩個index i,j 求出 最大值的 (nums[i]-1)* (nums[j]-1)
## 初步解法:
### 初步觀察:
首先 因為都是正整數
所以知道 任意正整數 a, b, a * b的值跟a,b值為正相關
a,b 值越大 則 a * b 值越大
所以 這題相當於是在找尋 陣列最大的兩個值
### 初步設計:
Given a integer array nums
Step 0: let i = 0, max = 0, secondMax = 0
Step 1: if i >= len(nums) go to step 4
Step 2: if nums[i] > max then set secondMax = max, max = nums[i]
Step 3: if nums[i] <= max && nums[i] > secondMax set secondMax = nums[i]
Step 4: return (max - 1)* (secondMax - 1)
## 遇到的困難
### 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 max_product
func maxProduct(nums []int) int {
result := 0
max := 0
secondMax := 0
for _, val := range nums {
if val > max {
secondMax = max
max = val
} else if val > secondMax {
secondMax = val
}
}
result = (max - 1) * (secondMax - 1)
return result
}
```
## 測資的撰寫
```golang
package max_product
import "testing"
func Test_maxProduct(t *testing.T) {
type args struct {
nums []int
}
tests := []struct {
name string
args args
want int
}{
{
name: "Example1",
args: args{
nums: []int{3, 4, 5, 2},
},
want: 12,
},
{
name: "Example2",
args: args{
nums: []int{1, 5, 4, 5},
},
want: 16,
},
{
name: "Example2",
args: args{
nums: []int{3, 7},
},
want: 12,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := maxProduct(tt.args.nums); got != tt.want {
t.Errorf("maxProduct() = %v, want %v", got, tt.want)
}
})
}
}
```
## my self record
[golang leetcode 30day 24th](https://hackmd.io/BKK9QlHKTcq9agHLc3zrRw?view)
## 參考文章
[golang test](https://ithelp.ithome.com.tw/articles/10204692)