add new files

Author: anakin

123. Best Time to Buy and Sell Stock III.go

@@ -0,0 +1,26 @@
+package main
+
+import "math"
+
+/**
+只能进行两次交易，因此一共有四个状态，互相之间转移
+*/
+
+func maxProfit(prices []int) int {
+	b1, b2 := math.MinInt32, math.MinInt32
+	s1, s2 := 0, 0
+	for i := 0; i < len(prices); i++ {
+		b1 = max(b1, -prices[i])
+		s1 = max(s1, b1+prices[i])
+		b2 = max(b2, s1-prices[i])
+		s2 = max(s2, b2+prices[i])
+	}
+	return s2
+}
+
+func max(x, y int) int {
+	if x > y {
+		return x
+	}
+	return y
+}

130. Surrounded Regions.go

@@ -0,0 +1,46 @@
+package main
+
+/**
+TODO not AC yet
+*/
+func solve(board [][]byte) {
+	l1 := len(board)
+	if l1 == 0 {
+		return
+	}
+	l2 := len(board[0])
+	if l2 == 0 {
+		return
+	}
+	//初始化访问数组
+	visit := make([][]bool, l1)
+	for i := 0; i < l1; i++ {
+		visit[i] = make([]bool, l2)
+	}
+	for i := 0; i < l1; i++ {
+		for j := 0; j < l2; j++ {
+			if !visit[i][j] {
+				helper(board, visit, i, j)
+			}
+		}
+	}
+}
+
+func helper(board [][]byte, visit [][]bool, x, y int) bool {
+	if x < 0 || x >= len(board) || y < 0 || y >= len(board[0]) {
+		return false
+	}
+	if visit[x][y] {
+		return board[x][y] != 'O'
+	}
+	visit[x][y] = true
+	flag := true
+	if board[x][y] == 'O' {
+		board[x][y] = 'X'
+		flag = helper(board, visit, x+1, y) && helper(board, visit, x-1, y) && helper(board, visit, x, y+1) && helper(board, visit, x, y-1)
+		if flag == false {
+			board[x][y] = 'O'
+		}
+	}
+	return flag
+}

445. Add Two Numbers II.go

@@ -0,0 +1,48 @@
+package main
+
+/**
+节点顺序入栈
+*/
+func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
+	len1, len2 := 0, 0
+	for tmp := l1; tmp != nil; tmp = tmp.Next {
+		len1++
+	}
+	for tmp := l2; tmp != nil; tmp = tmp.Next {
+		len2++
+	}
+	if len1 < len2 {
+		l1, l2, len1, len2 = l2, l1, len2, len1
+	}
+	s1, s2 := make([]*ListNode, 0, len1), make([]*ListNode, 0, len2)
+	for tmp := l1; tmp != nil; tmp = tmp.Next {
+		s1 = append(s1, tmp)
+	}
+	for tmp := l2; tmp != nil; tmp = tmp.Next {
+		s2 = append(s2, tmp)
+	}
+
+	var head ListNode
+	add, i, t := 0, 0, 0
+	for i = 1; i <= len1; i++ {
+		if i <= len2 {
+			t = s1[len1-i].Val + s2[len2-i].Val + add
+		} else {
+			t = s1[len1-i].Val + add
+		}
+		add = t / 10
+		node := &ListNode{
+			t % 10,
+			head.Next,
+		}
+		head.Next = node
+	}
+	if add > 0 {
+		node := &ListNode{
+			add,
+			head.Next,
+		}
+		head.Next = node
+	}
+	return head.Next
+}