Merge pull request #929 from 0xff-dev/1701

Add solution and test-cases for problem 1701

Author: 6boris

leetcode/1701-1800/1701.Average-Waiting-Time/README.md

@@ -1,28 +1,39 @@
 # [1701.Average Waiting Time][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+There is a restaurant with a single chef. You are given an array `customers`, where `customers[i] = [arrivali, timei]`:
+
+- `arrivali` is the arrival time of the i<sup>th</sup> customer. The arrival times are sorted in **non-decreasing** order.
+- `timei` is the time needed to prepare the order of the i<sup>th</sup> customer.
+
+When a customer arrives, he gives the chef his order, and the chef starts preparing it once he is idle. The customer waits till the chef finishes preparing his order. The chef does not prepare food for more than one customer at a time. The chef prepares food for customers **in the order they were given in the input**.
+
+Return the **average** waiting time of all customers. Solutions within `10^-5` from the actual answer are considered accepted.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: customers = [[1,2],[2,5],[4,3]]
+Output: 5.00000
+Explanation:
+1) The first customer arrives at time 1, the chef takes his order and starts preparing it immediately at time 1, and finishes at time 3, so the waiting time of the first customer is 3 - 1 = 2.
+2) The second customer arrives at time 2, the chef takes his order and starts preparing it at time 3, and finishes at time 8, so the waiting time of the second customer is 8 - 2 = 6.
+3) The third customer arrives at time 4, the chef takes his order and starts preparing it at time 8, and finishes at time 11, so the waiting time of the third customer is 11 - 4 = 7.
+So the average waiting time = (2 + 6 + 7) / 3 = 5.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Average Waiting Time
-```go
 ```
-
+Input: customers = [[5,2],[5,4],[10,3],[20,1]]
+Output: 3.25000
+Explanation:
+1) The first customer arrives at time 5, the chef takes his order and starts preparing it immediately at time 5, and finishes at time 7, so the waiting time of the first customer is 7 - 5 = 2.
+2) The second customer arrives at time 5, the chef takes his order and starts preparing it at time 7, and finishes at time 11, so the waiting time of the second customer is 11 - 5 = 6.
+3) The third customer arrives at time 10, the chef takes his order and starts preparing it at time 11, and finishes at time 14, so the waiting time of the third customer is 14 - 10 = 4.
+4) The fourth customer arrives at time 20, the chef takes his order and starts preparing it immediately at time 20, and finishes at time 21, so the waiting time of the fourth customer is 21 - 20 = 1.
+So the average waiting time = (2 + 6 + 4 + 1) / 4 = 3.25.
+```
 
 ## 结语
 

leetcode/1701-1800/1701.Average-Waiting-Time/Solution.go

@@ -1,5 +1,14 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(customers [][]int) float64 {
+	sum, end := 0, 0
+	for _, c := range customers {
+		sum += c[1]
+		if c[0] < end {
+			sum += end - c[0]
+		}
+
+		end = max(end+c[1], c[0]+c[1])
+	}
+	return float64(sum) / float64(len(customers))
 }

leetcode/1701-1800/1701.Average-Waiting-Time/Solution_test.go

@@ -1,39 +1,49 @@
 package Solution
 
 import (
-	"reflect"
 	"strconv"
 	"testing"
 )
 
+const (
+	within = 1e-5
+)
+
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs [][]int
+		expect float64
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", [][]int{
+			{1, 2}, {2, 5}, {4, 3},
+		}, 5.00000},
+		{"TestCase2", [][]int{
+			{5, 2}, {5, 4}, {10, 3}, {20, 1},
+		}, 3.25000},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
 			got := Solution(c.inputs)
-			if !reflect.DeepEqual(got, c.expect) {
+			diff := got - c.expect
+			if diff < 0 {
+				diff = -diff
+			}
+			if diff > within {
 				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
 					c.expect, got, c.inputs)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }