"Problem: Given an input string txt consisting of alphanumeric characters and the parentheses characters '(' & ')', write a function which removes the minimum number of characters to return a version of the string with properly balanced parenthesis.
Answer: You can do this with a counter.
Psuedo-Python
Start with counter = 0
output = []
Iterate through the string, every time you encounter a '(', increment the counter. Add the character to the output.
If you encounter a ')', decrement the coun"
Michael B. - "Problem: Given an input string txt consisting of alphanumeric characters and the parentheses characters '(' & ')', write a function which removes the minimum number of characters to return a version of the string with properly balanced parenthesis.
Answer: You can do this with a counter.
Psuedo-Python
Start with counter = 0
output = []
Iterate through the string, every time you encounter a '(', increment the counter. Add the character to the output.
If you encounter a ')', decrement the coun"See full answer
"\# Definition for a binary tree node.
class TreeNode:
def init(self, val=0, left=None, right=None):
self.val = val
self.left = left
self.right = right
class Solution:
def maxPathSum(self, root: TreeNode) -> int:
self.max_sum = float('-inf')"
Jerry O. - "\# Definition for a binary tree node.
class TreeNode:
def init(self, val=0, left=None, right=None):
self.val = val
self.left = left
self.right = right
class Solution:
def maxPathSum(self, root: TreeNode) -> int:
self.max_sum = float('-inf')"See full answer
"SELECT
items.item_category,
SUM(orders.orderquantity) AS totalunitsorderedlast7days
FROM orders
JOIN items
ON orders.itemid = items.itemid
WHERE orders.order_date BETWEEN DATE('now', '-6 days') AND DATE('now')
GROUP BY items.item_category
`"
Salome L. - "SELECT
items.item_category,
SUM(orders.orderquantity) AS totalunitsorderedlast7days
FROM orders
JOIN items
ON orders.itemid = items.itemid
WHERE orders.order_date BETWEEN DATE('now', '-6 days') AND DATE('now')
GROUP BY items.item_category
`"See full answer
Coding
SQL
🧠 Want an expert answer to a question? Saving questions lets us know what content to make next.
"SELECT name, type,
CASE
WHEN type = 'Electronic' THEN price-(0.10*price)
WHEN type = 'Clothing' THEN price-(0.20*price)
WHEN type = 'Grocery' THEN price-(0.05*price)
WHEN type = 'Book' THEN price-(0.15*price)
ELSE price
END AS discounted_price
FROM products;
`"
Akshay D. - "SELECT name, type,
CASE
WHEN type = 'Electronic' THEN price-(0.10*price)
WHEN type = 'Clothing' THEN price-(0.20*price)
WHEN type = 'Grocery' THEN price-(0.05*price)
WHEN type = 'Book' THEN price-(0.15*price)
ELSE price
END AS discounted_price
FROM products;
`"See full answer
"Count items between indices within compartments
compartments are delineated by by: '|'
items are identified by: '*'
input_inventory = "*||||"
inputstartidxs = [1, 4, 6]
inputendidxs = [9, 5, 8]
expected_output = [3, 0, 1]
Explanation:
"*||||"
0123456789... indices
++ + # within compartments
^ start_idx = 1
^ end_idx = 9
-- - # within idxs but not within compartments
"*||||"
0123456789... indices
"
Anonymous Unicorn - "Count items between indices within compartments
compartments are delineated by by: '|'
items are identified by: '*'
input_inventory = "*||||"
inputstartidxs = [1, 4, 6]
inputendidxs = [9, 5, 8]
expected_output = [3, 0, 1]
Explanation:
"*||||"
0123456789... indices
++ + # within compartments
^ start_idx = 1
^ end_idx = 9
-- - # within idxs but not within compartments
"*||||"
0123456789... indices
"See full answer
"def find_first(array: List[int], num: int) -> int:
lo = 0
hi = len(array)-1
while lo = num:
hi = mid - 1
if lo == mid and array[mid] == num:
return mid
else:
array[mid] < num
lo = mid + 1
return -1
`"
Gabriele G. - "def find_first(array: List[int], num: int) -> int:
lo = 0
hi = len(array)-1
while lo = num:
hi = mid - 1
if lo == mid and array[mid] == num:
return mid
else:
array[mid] < num
lo = mid + 1
return -1
`"See full answer
"Questions to ask :
Are there negative values in the input array? Interview : YES
Will the product of two number fit into 32-bit Integer. If not, will it fit 64-bit Integer. If not, then is it safe to use Big Integer? Interview : let's worry only about 32 bit Integer
What should we return if the input array is null or size (size of input array) is less than 2? Return 0
From above Information:
General approach is as follows :
a) Track smallest 2 elements in the array -> p"
Rajendra D. - "Questions to ask :
Are there negative values in the input array? Interview : YES
Will the product of two number fit into 32-bit Integer. If not, will it fit 64-bit Integer. If not, then is it safe to use Big Integer? Interview : let's worry only about 32 bit Integer
What should we return if the input array is null or size (size of input array) is less than 2? Return 0
From above Information:
General approach is as follows :
a) Track smallest 2 elements in the array -> p"See full answer
"Even more faster and vectorized version, using np.linalg.norm - to avoid loop and np.argpartition to select lowest k. We dont need to sort whole array - we need to be sure that first k elements are lower than the rest.
import numpy as np
def knn(Xtrain, ytrain, X_new, k):
distances = np.linalg.norm(Xtrain - Xnew, axis=1)
k_indices = np.argpartition(distances, k)[:k] # O(N) selection instead of O(N log N) sort
return int(np.sum(ytrain[kindices]) > k / 2.0)
`"
Dinar M. - "Even more faster and vectorized version, using np.linalg.norm - to avoid loop and np.argpartition to select lowest k. We dont need to sort whole array - we need to be sure that first k elements are lower than the rest.
import numpy as np
def knn(Xtrain, ytrain, X_new, k):
distances = np.linalg.norm(Xtrain - Xnew, axis=1)
k_indices = np.argpartition(distances, k)[:k] # O(N) selection instead of O(N log N) sort
return int(np.sum(ytrain[kindices]) > k / 2.0)
`"See full answer
"from typing import List
def three_sum(nums: List[int]) -> List[List[int]]:
nums.sort()
triplets = set()
for i in range(len(nums) - 2):
firstNum = nums[i]
l = i + 1
r = len(nums) - 1
while l 0:
r -= 1
elif potentialSum < 0:
l += 1
"
Anonymous Roadrunner - "from typing import List
def three_sum(nums: List[int]) -> List[List[int]]:
nums.sort()
triplets = set()
for i in range(len(nums) - 2):
firstNum = nums[i]
l = i + 1
r = len(nums) - 1
while l 0:
r -= 1
elif potentialSum < 0:
l += 1
"See full answer
"
from typing import List
def getnumberof_islands(binaryMatrix: List[List[int]]) -> int:
if not binaryMatrix: return 0
rows = len(binaryMatrix)
cols = len(binaryMatrix[0])
islands = 0
for r in range(rows):
for c in range(cols):
if binaryMatrixr == 1:
islands += 1
dfs(binaryMatrix, r, c)
return islands
def dfs(grid, r, c):
if (
r = len(grid)
"
Rick E. - "
from typing import List
def getnumberof_islands(binaryMatrix: List[List[int]]) -> int:
if not binaryMatrix: return 0
rows = len(binaryMatrix)
cols = len(binaryMatrix[0])
islands = 0
for r in range(rows):
for c in range(cols):
if binaryMatrixr == 1:
islands += 1
dfs(binaryMatrix, r, c)
return islands
def dfs(grid, r, c):
if (
r = len(grid)
"See full answer
"function findPrimes(n) {
if (n < 2) return [];
const primes = [];
for (let i=2; i <= n; i++) {
const half = Math.floor(i/2);
let isPrime = true;
for (let prime of primes) {
if (i % prime === 0) {
isPrime = false;
break;
}
}
if (isPrime) {
primes.push(i);
}
}
return primes;
}
`"
Tiago R. - "function findPrimes(n) {
if (n < 2) return [];
const primes = [];
for (let i=2; i <= n; i++) {
const half = Math.floor(i/2);
let isPrime = true;
for (let prime of primes) {
if (i % prime === 0) {
isPrime = false;
break;
}
}
if (isPrime) {
primes.push(i);
}
}
return primes;
}
`"See full answer