Add solution problem 0122

src/0122.Best-Time-To-Buy-And-Sell-Stock-II/README.md

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+# [122. Best Time to Buy and Sell Stock II][title]
+
+## Description
+
+Say you have an array for which the ith element is the price of a given stock on day i.
+
+Design an algorithm to find the maximum profit. You may complete as many transactions as you like (i.e., buy one and sell one share of the stock multiple times).
+
+
+**Example 1:**
+
+```
+Input: [7,1,5,3,6,4]
+Output: 7
+Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4.
+ Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.
+```
+
+**Example 2:**
+
+```
+Input: [1,2,3,4,5]
+Output: 4
+Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4.
+ Note that you cannot buy on day 1, buy on day 2 and sell them later, as you are
+ engaging multiple transactions at the same time. You must sell before buying again.
+```
+
+**Example 3:**
+
+```
+Input: [7,6,4,3,1]
+Output: 0
+Explanation: In this case, no transaction is done, i.e. max profit = 0.
+```
+
+
+[title]: https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/

src/0122.Best-Time-To-Buy-And-Sell-Stock-II/Solution.go

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+package Solution
+
+func maxProfit(prices []int) int {
+maxProfit := 0
+for i := 0; i < len(prices)-1; i++ {
+if prices[i] < prices[i+1] {
+maxProfit += (prices[i+1] - prices[i])
+}
+}
+return maxProfit
+}

src/0122.Best-Time-To-Buy-And-Sell-Stock-II/Solution_test.go

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+package Solution
+
+import (
+"reflect"
+"testing"
+)
+
+func TestMaxProfit(t *testing.T) {
+cases := []struct {
+name string
+inputs []int
+expect int
+}{
+{"TestCase 1", []int{7, 1, 5, 3, 6, 4}, 7},
+{"TestCase 2", []int{1, 2, 3, 4, 5}, 4},
+{"TestCase 3", []int{7, 6, 4, 3, 1}, 0},
+}
+
+for _, testcase := range cases {
+t.Run(testcase.name, func(t *testing.T) {
+got := maxProfit(testcase.inputs)
+if !reflect.DeepEqual(got, testcase.expect) {
+t.Fatalf("expected: %v, but got %v, with inputs : %v", testcase.expect, got, testcase.inputs)
+}
+})
+}
+
+}