121 accepted

Author: aQua

Algorithms/0121.best-time-to-buy-and-sell-stock/README.md

@@ -4,19 +4,19 @@
 Say you have an array for which the ith element is the price of a given stock on day i.
 
 If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.
-```
 Example 1:
+```
 Input: [7, 1, 5, 3, 6, 4]
 Output: 5
-```
 max. difference = 6-1 = 5 (not 7-1 = 6, as selling price needs to be larger than buying price)
 
 ```
 Example 2:
+```
 Input: [7, 6, 4, 3, 1]
 Output: 0
-```
 In this case, no transaction is done, i.e. max profit = 0.
+```
 
 ## 解题思路
 

Algorithms/0121.best-time-to-buy-and-sell-stock/best-time-to-buy-and-sell-stock.go

@@ -1,5 +1,14 @@
 package Problem0121
 
 func maxProfit(prices []int) int {
+	max := 0
+	for i, v := range prices {
+		for j := i + 1; j < len(prices); j++ {
+			if max < prices[j]-v {
+				max = prices[j] - v
+			}
+		}
+	}
 
+	return max
 }

Algorithms/0121.best-time-to-buy-and-sell-stock/best-time-to-buy-and-sell-stock_test.go

@@ -1,8 +1,8 @@
 package Problem0121
 
 import (
-	"testing"
 	"fmt"
+	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -19,7 +19,7 @@ type para struct {
 
 // ans 是答案
 type ans struct {
-	one  int 
+	one int
 }
 
 func Test_Problem0121(t *testing.T) {
@@ -29,20 +29,29 @@ func Test_Problem0121(t *testing.T) {
 
 		question{
 			para{
-					,
+				[]int{7, 1, 5, 3, 6, 4},
+			},
+			ans{
+				5,
+			},
+		},
+
+		question{
+			para{
+				[]int{7, 6, 5, 4, 3, 2, 1},
 			},
 			ans{
-					,
+				0,
 			},
 		},
-	
+
 		// 如需多个测试，可以复制上方元素。
 	}
 
 	for _, q := range qs {
 		a, p := q.ans, q.para
 		fmt.Printf("~~%v~~\n", p)
 
-		ast.Equal(a.one, maxProfit(p.prices ), "输入:%v", p)
+		ast.Equal(a.one, maxProfit(p.prices), "输入:%v", p)
 	}
 }