Codeforces Round 649 (Div. 2)

4 problems from Codeforces Round 649 (Div. 2) (contest 1364), difficulty 1200-2700. 1/4 solutions verified against sample I/O.

4 items

Codeforces Round 649 (Div. 2)

Div. 2 | 4 problems | 1/4 verified | Difficulty 1200-2700 | 14m 36s

#	Problem	Rating	Tags	Accepted	Time	✓
A	XXXXX	1200	brute-force, data-structures, number-theory	31,358	1m 54s	✓
B	Most socially-distanced subsequence	1300	greedy, two-pointers	26,161	6m 7s
C	Ehab and Prefix MEXs	1600	brute-force, constructive-algorithms, greedy	14,348	2m 55s
E	X-OR	2700	bitmasks, constructive-algorithms, divide-and-conquer	1,551	3m 40s

Practice › Codeforces Solutions › Codeforces Round 649 (Div. 2) ›

CF 1364B - Most socially-distanced subsequence

We are given a permutation, which means every number from 1 to n appears exactly once, just in some order. From this array we are allowed to delete elements and keep the remaining ones in the same relative order, forming a subsequence.

Practice › Codeforces Solutions › Codeforces Round 649 (Div. 2) ›

CF 1364E - X-OR

We are given a hidden arrangement of the numbers from 0 to n−1 placed at indices 1 through n. The only way to gain information is to choose two different positions and receive the bitwise OR of the values stored at those positions.

Practice › Codeforces Solutions › Codeforces Round 649 (Div. 2) ›

CF 1364C - Ehab and Prefix MEXs

The exercise asks us to investigate approximate polynomial greatest common divisors (gcds) and the behavior of Euclid's algorithm when the polynomial coefficients are floating-point numbers.

Practice › Codeforces Solutions › Codeforces Round 649 (Div. 2) ›

CF 1364A - XXXXX

We are given an array of integers and a number $x$ that Ehab dislikes. The goal is to find the length of the longest contiguous subarray whose sum is not divisible by $x$. Each test case gives a new array and a new $x$.