adding Problem 33

accepted

Author: aQua

Algorithms/0033.search-in-rotated-sorted-array/README.md

@@ -1,7 +1,13 @@
 # [33. Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)
 
 ## 题目
+Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
 
+(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).
+
+You are given a target value to search. If found in the array return its index, otherwise return -1.
+
+You may assume no duplicate exists in the array.
 
 ## 解题思路
 

Algorithms/0033.search-in-rotated-sorted-array/search-in-rotated-sorted-array.go

@@ -1,2 +1,58 @@
 package Problem0033
 
+func search(nums []int, target int) int {
+	if len(nums) == 0 {
+		return -1
+	}
+
+	if nums[len(nums)-1] > nums[0] {
+		return searchInt(nums, target, 0)
+	}
+
+	base := searchMax(nums) + 1
+	res := searchInt(nums[:base], target, 0)
+	if res != -1 {
+		return res
+	}
+	res = searchInt(nums[base:], target, base)
+	if res != -1 {
+		return res
+	}
+
+	return -1
+}
+
+func searchInt(nums []int, target, base int) (index int) {
+	lo, hi := 0, len(nums)-1
+	for lo <= hi {
+		index = (lo + hi) / 2
+		switch {
+		case nums[index] > target:
+			hi = index - 1
+		case nums[index] < target:
+			lo = index + 1
+		default:
+			return base + index
+		}
+	}
+	return -1
+}
+
+func searchMax(nums []int) (index int) {
+	i, j := 0, len(nums)-1
+
+	for {
+		index = (i + j) / 2
+		if index == 0 || index == len(nums)-1 {
+			return
+		}
+		if index > 0 && index < len(nums)-1 && nums[index] > nums[index-1] && nums[index] > nums[index+1] {
+			return
+		}
+		if nums[index] > nums[i] {
+			i = index
+		} else {
+			j = index
+		}
+	}
+}

Algorithms/0033.search-in-rotated-sorted-array/search-in-rotated-sorted-array_test.go

@@ -1,8 +1,8 @@
 package Problem0033
 
 import (
-	"testing"
 	"fmt"
+	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -15,13 +15,14 @@ type question struct {
 // para 是参数
 // one 代表第一个参数
 type para struct {
-	one string
+	one []int
+	two int
 }
 
 // ans 是答案
 // one 代表第一个答案
 type ans struct {
-	one string
+	one int
 }
 
 func Test_Problem0033(t *testing.T) {
@@ -30,17 +31,79 @@ func Test_Problem0033(t *testing.T) {
 	qs := []question{
 
 		question{
-			para{""},
-			ans{""},
+			para{[]int{4, 5, 6, 7, 0, 1, 2}, 5},
+			ans{1},
+		},
+
+		question{
+			para{[]int{6, 7, 0, 1, 2,3,4,5}, 1},
+			ans{3},
+		},
+
+		question{
+			para{[]int{1, 3}, 0},
+			ans{-1},
+		},
+
+		question{
+			para{[]int{}, 5},
+			ans{-1},
+		},
+
+		question{
+			para{[]int{2}, 5},
+			ans{-1},
+		},
+
+		question{
+			para{[]int{2}, 2},
+			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, (p.one), "输入:%v", p)
+		ast.Equal(a.one, search(p.one, p.two), "输入:%v", p)
 	}
 }
+func Test_searchInt(t *testing.T) {
+	var actual, expected int
+	ast := assert.New(t)
+
+	actual = searchInt([]int{3, 4}, 4, 0)
+	expected = 1
+	ast.Equal(expected, actual)
+
+	actual = searchInt([]int{3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, 4, 0)
+	expected = 1
+	ast.Equal(expected, actual)
+}
+func Test_searchMax(t *testing.T) {
+	var actual, expected int
+	ast := assert.New(t)
+
+	actual = searchMax([]int{9, 1, 2, 3, 4, 5, 6, 7, 8})
+	expected = 0
+	ast.Equal(expected, actual)
+
+	actual = searchMax([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 0})
+	expected = 8
+	ast.Equal(expected, actual)
+
+	actual = searchMax([]int{4, 5, 6, 7, 0, 1, 2})
+	expected = 3
+	ast.Equal(expected, actual)
+
+	actual = searchMax([]int{1, 0})
+	expected = 0
+	ast.Equal(expected, actual)
+
+	actual = searchMax([]int{0})
+	expected = 0
+	ast.Equal(expected, actual)
+
+}