python-剑指offer

python 刷剑指offer
编程环境python2，OJ：牛客
1.二维数组中的查找

class Solution:
    # array 二维列表
    def Find(self, target, array):
        # write code here
        if len(array)==0 or len(array[0])==0:
            return False
        i = 0
        j = len(array[0])-1
        while(i<len(array) and j>=0):
            if array[i][j]==target:
                return True
            elif array[i][j]>target:
                j-=1
            else:
                i+=1
        return False

2.替换空格

class Solution:
    # s 源字符串
    def replaceSpace(self, s):
        #def replaceSpaceByAppend(self, s):
        if s == None:
            return None
        if len(s) == 0:
            return ''
        result = ''
        for item in s:
            if item.isspace():
                result = result+'%20'
            else:
                result = result+item
        return result

3.从头到尾打印链表

class Solution:
    # 返回从尾部到头部的列表值序列，例如[1,2,3]
    def printListFromTailToHead(self, listNode):
        # write code here
        ret = []
        head = listNode
        while(head):
            ret.append(head.val)
            head = head.next
        ret.reverse()
        return ret

4.重建二叉树

class Solution:
    # 返回构造的TreeNode根节点
    def reConstructBinaryTree(self, pre, tin):
        if pre==[]:
            return None
        val = pre[0]
        idx = tin.index(val)
        ltin = tin[0:idx]
        rtin = tin[idx+1:]
        lpre = pre[1:1+len(ltin)]
        rpre = pre[1+len(ltin):]
        root = TreeNode(val)
        root.left = self.reConstructBinaryTree(lpre,ltin)
        root.right = self.reConstructBinaryTree(rpre,rtin)
        return root

5.用两个栈实现队列

class Solution:
    def __init__(self):
        self.stack1 = []
        self.stack2 = []
    def push(self, node):
        # write code here
        self.stack1.append(node)

    def pop(self):
        # return xx
        if len(self.stack2):
            return self.stack2.pop()
        while(self.stack1):
            self.stack2.append(self.stack1.pop())
        return self.stack2.pop()

6.旋转数组的最小数字

class Solution:
    def minNumberInRotateArray(self, rotateArray):
        # write code here
        if rotateArray == []:
            return 0
        _len = len(rotateArray)
        left = 0
        right = _len -1
        while left <= right:
            mid = int((left + right) >> 1)
            if rotateArray[mid] < rotateArray[mid - 1]:
                return rotateArray[mid]
            if rotateArray[mid] >= rotateArray[right]:
                left = mid + 1
            else:
                right = mid - 1
        return rotateArray[mid]