通过测试

Author: aQua

Algorithms/0041.first-missing-positive/README.md

@@ -1,7 +1,14 @@
 # [41. First Missing Positive](https://leetcode.com/problems/first-missing-positive/)
 
 ## 题目
+Given an unsorted integer array, find the first missing positive integer.
 
+For example,
+```
+Given [1,2,0] return 3,
+and [3,4,-1,1] return 2.
+```
+Your algorithm should run in O(n) time and uses constant space.
 
 ## 解题思路
 

Algorithms/0041.first-missing-positive/first-missing-positive.go

@@ -1,2 +1,30 @@
 package Problem0041
 
+import "sort"
+
+func firstMissingPositive(nums []int) int {
+	if len(nums) == 0 {
+		return 1
+	}
+
+	sort.Ints(nums)
+	i := sort.SearchInts(nums, 0)
+	if nums[i] == 0 {
+		i++
+	}
+
+	res := 1
+	for i < len(nums) {
+		if 0 < i && nums[i] == nums[i-1] {
+			i++
+			continue
+		}
+		if nums[i] != res {
+			return res
+		}
+		i++
+		res++
+	}
+
+	return res
+}

Algorithms/0041.first-missing-positive/first-missing-positive_test.go

@@ -1,8 +1,8 @@
 package Problem0041
 
 import (
-	"testing"
 	"fmt"
+	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -15,13 +15,13 @@ type question struct {
 // para 是参数
 // one 代表第一个参数
 type para struct {
-	one string
+	one []int
 }
 
 // ans 是答案
 // one 代表第一个答案
 type ans struct {
-	one string
+	one int
 }
 
 func Test_Problem0041(t *testing.T) {
@@ -30,17 +30,37 @@ func Test_Problem0041(t *testing.T) {
 	qs := []question{
 
 		question{
-			para{""},
-			ans{""},
+			para{[]int{1}},
+			ans{2},
+		},
+
+		question{
+			para{[]int{0, 2, 2, 1, 1}},
+			ans{3},
+		},
+
+		question{
+			para{[]int{}},
+			ans{1},
 		},
-	
+
+		question{
+			para{[]int{1, 2, 0}},
+			ans{3},
+		},
+
+		question{
+			para{[]int{3, 4, -1, 1}},
+			ans{2},
+		},
+
 		// 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, (p.one), "输入:%v", p)
+		ast.Equal(a.one, firstMissingPositive(p.one), "输入:%v", p)
 	}
 }