Table of Contents

1. Warm up problems
2. Binary Search
3. Tree algorithms
4. Sweep line technique
5. Two pointers
6. Recursion
7. Dynamic Programming
8. Basic Data Structures
9. Greedy Algorithms

Many of the problems have been taken from here

Warm up problems

These problems are taken from TLE eliminators cp sheet

Problem source	Status	Tags	Remarks
CF 1883B	🟢Done	Observation	Can afford k+1 odd number of characters otherwise not possible to make a palindrome
CF 1904A	🟢Done	strings	First we have to findout from which places a king can be attacked then from those selected places we will again check if there is such position that also attacks the queen and those final places will be the answer
CF 1878C	🟢Done	Math	If the target sum lies between minimum and maximum possible sum of k integers then it is "YES" otherwise "NO"
CF 1875A	🟢Done	-	-
CF 1913B	🟢Done	-	-
CF 1883C	🟢Done	Observation	Special check for k = 4
**CF 1855B	🟢Done	Observation	x consecutive numbers wil always have atleast one divisor from 1 to x

Binary Search

BSTA - Binary Search The Answer

Problem source	Status	Tags	Remarks
Number of segments with big sum(CF EDU)	🟢Done	Prefix sum,(lower/upper bounds)	-
⭐CSES factory machine	🔴Revisit	Binary search	-
CF Edu - Binary search	🟢Done	Binary search	-
CF Edu - Closest to the left	🟢Done	Binary search	-
CF Edu - Closest to the right	🟢Done	Binary search	-
CF Edu - packing rectangles	🟢Done	Binary search BSTA	Check overflow during multiplication
CF Edu - ropes	🟢Done	Binary search BSTA	increment will be 1e-6
CF Edu - very easy task	🟢Done	Binary search BSTA	second machine will start only after the first machine has printed a copy
CF 1985F	🟢Done	Binary search BSTA	Check overflow
⭐Children hoilday	🟢Done	Binary search BSTA	check

Tree Algorithms

Problem source	Status	Tags
CSES Subordinates	🔴Revisit	DP DP on tree

Sweep Line technique

Problem source	Status	Remarks
CSES Restaurant Customers	🟢Done	Line sweep (Used vector)

Two pointers

Problem source	Status	Tags	Remarks
CF 1265	🔴Revisit	two pointer	-
**CSES sum of three values	🔴Revisit	two pointer	Use loop for the first value and two pointers for the rest two values
CF 279B	🔴Revisit	two pointer	-
Segment with small sum (CF Edu)	🟢Done	two pointer	Iterate the array with two pointers
CSES Ferris wheel	🟢Done	Sorting two pointer	-
CSES Playlist	🔴Revisit	two pointer sliding window	Use two pointers and keep track of the current segment

Recursion

Problem source	Status	Tags	Remarks
Beecrowd 1029	🟢Done	recursion	-

Dynamic Programming

Problem source	Status	Tags	Remarks
CSES Dice Combinations	🟢Done	DP	Iterate from the beginning and find out the solution
CSES Minimizing Coins	🟢Done	DP	Iterative DP
Lucas number (Atcoder)	🟢Done	DP	Basic iterative DP
Frog 2 (Atcoder)	🟢Done	DP	Basic iterative DP

Basic Data Structures & Algorithms

Problem source	Status	Tags	Remarks
Beecrowd 1068	🟢Done	stack	-
Beecrowd 1069	🟢Done	stack	-
Beecrowd 1566	🟢Done	counting sort	-

Greedy Algorithm

Problem source	Status	Tags	Remarks
⭐CF 1914D	🔴Using..DP	Greedy Sorting	-
CSES Missing coin sum	🟢Done	Observation	After sorting ,if a[i] is less than sum(a[0],a[i-1]) than it is possible to form all numbers from a[0] to sum(a[i-1]) so the missing sum will be sum(a[i-1])+a[i]
CSES Collecting Numbers	🟢Done	Greedy	check if the previous number has less index or not
CSES Tasks and Deadline	🟢Done	sorting	Sort tasks according to duration in ascending order
⭐CF 1520E	🟢Done	Greedy	Have to minimize the sum of non-starred cells