Day42_1204
专注时间：2h58min
每日任务：计算机网络50分钟(0分钟)，搜广推90分钟~上不封顶+手撕目录里的算法（0），二刷hot100算法题2道（完成4道），刑法实务考试复习50分钟（已经看完。不用再看了）
学习内容： 如上，好像都在做算法题，下午放学之后没去图书馆，所以没有专注时长，非常可惜、非常浪费了。
总结与心得： 明天不做算法题。
《54.螺旋矩阵》
python
class Solution(object):
def spiralOrder(self, matrix):
"""
:type matrix: List[List[int]]
:rtype: List[int]
"""
m = len(matrix)
n = len(matrix[0])
visited =[[False for _ in range(n)] for _ in range(m)]
dx = [0,1,0,-1]
dy = [1,0,-1,0]
x,y = 0,0
d=0
res = []
for k in range(n*m):
res.append(matrix[x][y])
visited[x][y]=True
newx = x + dx[d]
newy = y + dy[d]
if 0<=newx<m and 0<=newy<n and visited[newx][newy]==False:
x = newx
y = newy
else:
d = (d+1)%4
x+=dx[d]
y+=dy[d]
return res《48.旋转图像》
python
class Solution(object):
def rotate(self, matrix):
"""
:type matrix: List[List[int]]
:rtype: None Do not return anything, modify matrix in-place instead.
"""
n = len(matrix)
i,j = 0,n-1
while i<j:
for k in range(n):
matrix[i][k],matrix[j][k] = matrix[j][k],matrix[i][k]
i+=1
j-=1
for i in range(n):
for j in range(i+1):
matrix[i][j],matrix[j][i] = matrix[j][i],matrix[i][j]
python
class Solution(object):
def rotate(self, matrix):
"""
:type matrix: List[List[int]]
:rtype: None Do not return anything, modify matrix in-place instead.
"""
n = len(matrix)
helper = [[0 for _ in range(n)] for _ in range(n)]
for j in range(n-1,-1,-1):
for i in range(n):
helper[i][j] = matrix[n-1-j][i]
for i in range(n):
for j in range(n):
matrix[i][j] = helper[i][j]
《240.搜索二维矩阵②》
python
class Solution(object):
def searchMatrix(self, matrix, target):
"""
:type matrix: List[List[int]]
:type target: int
:rtype: bool
"""
m = len(matrix)
n = len(matrix[0])
for j in range(m):
if matrix[j][n-1]>=target:
for i in range(n):
if matrix[j][i] == target:
return True
return False
python
class Solution(object):
def erfen(self,nums,target):
l,r = 0,len(nums)-1
while l<r:
mid = (l+r)/2
if nums[mid]>=target:
r = mid
else:
l = mid+1
return nums[l]==target
def searchMatrix(self, matrix, target):
"""
:type matrix: List[List[int]]
:type target: int
:rtype: bool
"""
m = len(matrix)
n = len(matrix[0])
for j in range(m):
if matrix[j][n-1]>=target:
if matrix[j][n-1]==target:
return True
if self.erfen(matrix[j],target) is True:
return True
return False
python
class Solution(object):
def searchMatrix(self, matrix, target):
"""
:type matrix: List[List[int]]
:type target: int
:rtype: bool
"""
#z字形搜索
m = len(matrix)
n = len(matrix[0])
x,y = 0,n-1
while x<m and y>=0:
if matrix[x][y]==target:
return True
elif matrix[x][y]>target:
y-=1
else:
x+=1
return False《160.相交链表》
python
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def getIntersectionNode(self, headA, headB):
"""
:type head1, head1: ListNode
:rtype: ListNode
"""
if not headA or not headB:
return None
p,q = headA,headB
while p!=q:
p = p.next if p else headB
q = q.next if q else headA
return p
python
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def getIntersectionNode(self, headA, headB):
"""
:type head1, head1: ListNode
:rtype: ListNode
"""
if not headA or not headB:
return None
occ = set()
q = headA
while q:
occ.add(q)
q=q.next
p = headB
while p:
if p in occ:
return p
p=p.next
return None