977.有序数组的平方
Python
#最后反转列表
class Solution:
def sortedSquares(self, nums: List[int]) -> List[int]:
left,right=0,len(nums)-1
new_nums=[]
while left<=right:
num1=nums[left]**2
num2=nums[right]**2
if num1<num2:
new_nums.append(num2)
right-=1
else:
new_nums.append(num1)
left+=1
new_nums.reverse()
return new_nums
#用deque
from collections import deque
class Solution:
def sortedSquares(self, nums: List[int]) -> List[int]:
left,right=0,len(nums)-1
new_nums=deque()
while left<=right:
num1=nums[left]**2
num2=nums[right]**2
if num1<num2:
new_nums.appendleft(num2)
right-=1
else:
new_nums.appendleft(num1)
left+=1
return list(new_nums)
C++
#用reverse
class Solution {
public:
vector<int> sortedSquares(vector<int>& nums) {
vector<int>new_nums;
int left=0,right=nums.size()-1;
while (left<=right){
int num1=nums[left]*nums[left];
int num2=nums[right]*nums[right];
if (num1<num2){
new_nums.push_back(num2);
right--;
}else{
new_nums.push_back(num1);
left++;
}
}
reverse(new_nums.begin(), new_nums.end());
return new_nums;
}
};
#用deque
class Solution {
public:
vector<int> sortedSquares(vector<int>& nums) {
deque<int>new_nums;
int left=0,right=nums.size()-1;
while (left<=right){
int num1=nums[left]*nums[left];
int num2=nums[right]*nums[right];
if (num1<num2){
new_nums.push_front(num2);
right--;
}else{
new_nums.push_front(num1);
left++;
}
}
vector<int>myVector(new_nums.begin(),new_nums.end());
return myVector;
}
};
209.长度最小的子数组
Python
class Solution:
def minSubArrayLen(self, target: int, nums: List[int]) -> int:
slow=0
total=0
result=float("inf")
for fast in range(len(nums)):
total+=nums[fast]
while total>=target:
result=min(result,fast+1-slow)
total-=nums[slow]
slow+=1
return result if result!=float("inf") else 0
C++
class Solution {
public:
int minSubArrayLen(int target, vector<int>& nums) {
int slow=0,total=0;
long long result=1e18;
for (int fast=0;fast<nums.size();fast++){
total+=nums[fast];
while (total>=target){
result=result<fast-slow+1?result:fast-slow+1;
total-=nums[slow];
slow++;
}
}
return result==1e18?0:result;
}
};
59.螺旋矩阵II
Python
class Solution:
def generateMatrix(self, n: int) -> List[List[int]]:
nums = [[0] * n for _ in range(n)]
startx, starty = 0, 0 # 起始点
loop, mid = n // 2, n // 2 # 迭代次数、n为奇数时,矩阵的中心点
count = 1 # 计数
for offset in range(1, loop + 1) : # 每循环一层偏移量加1,偏移量从1开始
for i in range(starty, n - offset) : # 从左至右,左闭右开
nums[startx][i] = count
count += 1
for i in range(startx, n - offset) : # 从上至下
nums[i][n - offset] = count
count += 1
for i in range(n - offset, starty, -1) : # 从右至左
nums[n - offset][i] = count
count += 1
for i in range(n - offset, startx, -1) : # 从下至上
nums[i][starty] = count
count += 1
startx += 1 # 更新起始点
starty += 1
if n % 2 != 0 : # n为奇数时,填充中心点
nums[mid][mid] = count
return nums
总结
二刷了,这道题还是没有写出来,之前记的方法都忘记了,不过也是有了新的感悟。