add new files

Author: anakin

33. Search in Rotated Sorted Array.go

@@ -0,0 +1,32 @@
+package main
+
+func search(nums []int, target int) int {
+	lo := 0
+	hi := len(nums) - 1
+
+	for lo < hi {
+		mid := (lo + hi) / 2
+		if nums[mid] == target {
+			return mid
+		}
+		if nums[lo] <= nums[mid] {
+			if target >= nums[lo] && target < nums[mid] {
+				hi = mid - 1
+			} else {
+				lo = mid + 1
+			}
+		} else {
+			if target > nums[mid] && target <= nums[hi] {
+				lo = mid + 1
+			} else {
+				hi = mid - 1
+			}
+		}
+
+	}
+	if nums[lo] == target {
+		return lo
+	} else {
+		return -1
+	}
+}

35. Search Insert Position.go

@@ -0,0 +1,37 @@
+package main
+
+func searchInsert(nums []int, target int) int {
+	if target < nums[0] {
+		return 0
+	}
+	l := len(nums)
+	if target > nums[l-1] {
+		return l
+	}
+	left, right := 0, l-1
+	for left <= right {
+		m := (left + right) / 2
+		if nums[m] > target {
+			right = m - 1
+			if right >= 0 {
+				if nums[right] < target {
+					return right + 1
+				}
+			} else {
+				return 0
+			}
+		} else if nums[m] < target {
+			left = m + 1
+			if left < l {
+				if nums[left] > target {
+					return left
+				}
+			} else {
+				return l
+			}
+		} else {
+			return m
+		}
+	}
+	return 0
+}

38. Count and Say.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"strconv"
+)
+
+func countAndSay(n int) string {
+	if n == 1 {
+		return "1"
+	}
+	return count(countAndSay(n - 1))
+}
+
+func count(s string) string {
+	c := string(s[0])
+	count := 1
+	res := ""
+	for _, char := range s[1:] {
+		if string(char) == c {
+			count += 1
+		} else {
+			res = res + strconv.Itoa(count) + string(c)
+			c = string(char)
+			count = 1
+		}
+	}
+	res = res + strconv.Itoa(count) + string(c)
+	return res
+}

53. Maximum Subarray.go

@@ -0,0 +1,17 @@
+package main
+
+func maxSubArray(nums []int) int {
+	cur := nums[0]
+	sum := nums[0]
+	for i := 1; i < len(nums); i++ {
+		if sum >= 0 {
+			sum += nums[i]
+		} else {
+			sum = nums[i]
+		}
+		if cur < sum {
+			cur = sum
+		}
+	}
+	return cur
+}

56. Merge Intervals.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"sort"
+)
+
+type Interval struct {
+	Start int
+	End   int
+}
+
+func merge(intervals []Interval) []Interval {
+	l := len(intervals)
+	var (
+		starts []int
+		ends   []int
+		res    []Interval
+	)
+	for _, v := range intervals {
+		starts = append(starts, v.Start)
+		ends = append(ends, v.End)
+	}
+	sort.Ints(starts)
+	sort.Ints(ends)
+	for i, j := 0, 0; i < l; i++ {
+		if i == l-1 || starts[i+1] > ends[i] { //中间出现了不连续，记录前一个连续值
+			res = append(res, Interval{Start: starts[j], End: ends[i]})
+			j = i + 1
+		}
+	}
+	return res
+}

58. Length of Last Word.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"strings"
+)
+
+func lengthOfLastWord(s string) int {
+	arr := strings.Split(strings.Trim(s, " "), " ")
+	length := len(arr)
+	res := 0
+	for i := length - 1; i >= 0; i-- {
+		if arr[i] == " " {
+			continue
+		} else {
+			res = len(arr[i])
+			break
+		}
+	}
+	return res
+}

61. Rotate List.go

@@ -0,0 +1,26 @@
+package main
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func rotateRight(head *ListNode, k int) *ListNode {
+	if head == nil || head.Next == nil || k == 0 {
+		return head
+	}
+	len := 1
+	tail := head
+	for tail.Next != nil {
+		tail = tail.Next
+		len++
+	}
+	tail.Next = head //变成一个环
+	k = k % len      //因为是个环，所以不用转超过一圈
+	for i := 0; i < len-k; i++ {
+		tail = tail.Next
+	}
+	head = tail.Next
+	tail.Next = nil
+	return head
+}