add new files

Author: anakin

Diff for: 14. Longest Common Prefix.go

@@ -0,0 +1,27 @@
+package main
+
+import "math"
+
+func longestCommonPrefix(strs []string) string {
+	if len(strs) == 0 {
+		return ""
+	}
+	minLen := math.MaxInt32
+	minStr := ""
+	for _, v := range strs {
+		l := len(v)
+		if l < minLen {
+			minLen = l
+			minStr = v
+		}
+	}
+	long := len(minStr)
+	for _, v := range strs {
+		for i := 0; i < minLen; i++ {
+			if minStr[i:i+1] != v[i:i+1] {
+				long = int(math.Min(float64(long), float64(i)))
+			}
+		}
+	}
+	return minStr[:long]
+}

Diff for: 15. 3Sum.go

@@ -0,0 +1,37 @@
+package main
+
+import "sort"
+
+func threeSum(nums []int) [][]int {
+	sort.Ints(nums)
+	res := make([][]int, 0)
+	f := func(nums []int, begin int, end int, target int) {
+		for begin < end {
+			if nums[begin]+nums[end]+target == 0 {
+				r := make([]int, 0)
+				r = append(r, nums[begin], nums[end], target)
+				res = append(res, r)
+				for begin < end && nums[begin] == nums[begin+1] {
+					begin++
+				}
+				for begin < end && nums[end] == nums[end-1] {
+					end--
+				}
+				begin++
+				end--
+			} else if (target + nums[begin] + nums[end]) < 0 {
+				begin++
+			} else {
+				end--
+			}
+		}
+	}
+	l := len(nums)
+	for i := 0; i < l-2; i++ {
+		if i > 0 && nums[i] == nums[i-1] {
+			continue
+		}
+		f(nums, i+1, l-1, nums[i])
+	}
+	return res
+}

Diff for: 19. Remove Nth Node From End of List.go

@@ -0,0 +1,27 @@
+package main
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+/**
+* 快慢指针
+ */
+func removeNthFromEnd(head *ListNode, n int) *ListNode {
+	cur := head
+	last := head
+	for i := 0; i < n; i++ {
+		if cur.Next != nil {
+			cur = cur.Next
+		} else {
+			return head.Next
+		}
+	}
+	for cur.Next != nil {
+		cur = cur.Next
+		last = last.Next
+	}
+	last.Next = last.Next.Next
+	return head
+}

Diff for: 21. Merge Two Sorted Lists.go

@@ -0,0 +1,23 @@
+package main
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func mergeTwoLists(l1 *ListNode, l2 *ListNode) *ListNode {
+	if l1 == nil {
+		return l2
+	}
+	if l2 == nil {
+		return l1
+	}
+	if l1.Val < l2.Val {
+		l1.Next = mergeTwoLists(l1.Next, l2)
+		return l1
+	} else {
+		l2.Next = mergeTwoLists(l1, l2.Next)
+		return l2
+	}
+
+}

Diff for: 26. Remove Duplicates from Sorted Array.go

@@ -0,0 +1,14 @@
+package main
+
+func removeDuplicates(nums []int) int {
+	for i, j := 0, 1; i < j && j < len(nums); {
+		if nums[j] == nums[i] {
+			nums = append(nums[:i], nums[i+1:]...)
+			j--
+			i--
+		}
+		j++
+		i++
+	}
+	return len(nums)
+}

Diff for: 27. Remove Element.go

@@ -0,0 +1,17 @@
+package main
+
+func removeElement(nums []int, val int) int {
+
+	if nums == nil {
+		return 0
+	}
+	for i := 0; i < len(nums); {
+		if nums[i] == val {
+			nums = append(nums[:i], nums[i+1:]...)
+			i--
+		}
+		i++
+	}
+	return len(nums)
+
+}