left = mid + 1;

O(n log n)

const memo = new Map();

while (l < r) { mid = (l+r)/2; }

return dfs(root.left) + dfs(root.right);

def solve(nums):

left = mid + 1;

stack.push(node);

for (int i=0; i<n; i++) {

left = mid + 1;

swap(a[i], a[j]);

graph[u].push_back(v);

map<int,int> freq;

return root == null;

prefix[i] = prefix[i-1] + a[i];

if (visited[u]) continue;

return root == null;

O(n log n)

Raj Vikramaditya (takeUforward)

Striver A2Z DSA Sheet

474 problems · The community-loved A2Z sheet — beginner to advanced, organized step-by-step by topic.

Learn the basics

54 problems · 7 groups

#	Problem	Difficulty	Companies	Practice
1	Input Output	Easy	—	takeUforward
2	Cpp Basics	Easy	—	takeUforward
3	If ElseIf	Easy	—	takeUforward
4	Switch Case	Easy	—	takeUforward
5	What are arrays, strings?	Easy	—	takeUforward
6	For loops	Easy	—	takeUforward

3 more problems in this group — unlock with Resume Pro.

#	Problem	Difficulty	Companies	Practice
1	Easy and Medium	Easy	—	takeUforward
2	Hard	Easy	—	takeUforward

#	Problem	Difficulty	Companies	Practice
1	Pattern 1	Easy	—	takeUforward
2	Pattern 2	Easy	—	takeUforward
3	Pattern 3	Easy	—	takeUforward
4	Pattern 4	Easy	—	takeUforward
5	Pattern 5	Easy	—	takeUforward
6	Pattern 6	Easy	—	takeUforward

16 more problems in this group — unlock with Resume Pro.

#	Problem	Difficulty	Companies	Practice
1	STL	Easy	—	takeUforward
2	Java Collections	Easy	—	takeUforward

#	Problem	Difficulty	Companies	Practice
1	Count all Digits of a Number	Easy	—	takeUforward
2	Reverse a number	Easy	—	LeetCode takeUforward
3	Palindrome Number	Easy	—	LeetCode takeUforward
4	GCD of Two Numbers	Easy	—	takeUforward
5	Check if the Number is Armstrong	Easy	—	LeetCode takeUforward
6	Print all Divisors	Easy	—	takeUforward

1 more problems in this group — unlock with Resume Pro.

#	Problem	Difficulty	Companies	Practice
1	Understand recursion by print something N times	Easy	—	takeUforward
2	Print name N times using recursion	Easy	—	takeUforward
3	Print 1 to N using Recursion	Easy	—	takeUforward
4	Print N to 1 using Recursion	Easy	—	takeUforward
5	Sum of First N Numbers	Easy	—	takeUforward
6	Factorial of a given number	Easy	—	takeUforward

3 more problems in this group — unlock with Resume Pro.

#	Problem	Difficulty	Companies	Practice
1	Basic Hashing	Easy	—	takeUforward
2	Counting Frequencies of Array Elements	Easy	—	takeUforward
3	Highest Occurring Element in an Array	Easy	—	LeetCode takeUforward

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