Codeforces Round 1068 (Div. 2)

6 problems from Codeforces Round 1068 (Div. 2) (contest 2173), difficulty 800-2600. 3/6 solutions verified against sample I/O.

6 items

Codeforces Round 1068 (Div. 2)

Div. 2 | 6 problems | 3/6 verified | Difficulty 800-2600 | 14m 56s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Sleeping Through Classes	800	greedy, implementation	23,762	3m 6s	✓
B	Niko's Tactical Cards	1100	dp, greedy, math	18,108	2m 28s	✓
C	Kanade's Perfect Multiples	1400	brute-force, constructive-algorithms, greedy	12,364	1m 38s
D	Taiga's Carry Chains	1900	bitmasks, brute-force, dp	3,631	1m 58s
E	Shiro's Mirror Duel	2200	constructive-algorithms, greedy, interactive	1,533	2m 26s
F	Isla's Memory Thresholds	2600	binary-search, brute-force, data-structures	562	3m 20s	✓

Practice › Codeforces Solutions › Codeforces Round 1068 (Div. 2) ›

CF 2173F - Isla's Memory Thresholds

We are given a non-increasing array of positive integers, and we repeatedly process subsegments of it under a “capacity reset” rule. For each query, we pick a contiguous slice from index l to r. We then scan it left to right, maintaining a running sum.

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CF 2173E - Shiro's Mirror Duel

We maintain a permutation of 1..n. A query chooses two indices x and y. The judge then flips a coin. Either positions (x,y) are swapped, or their mirrored positions (n-x+1, n-y+1) are swapped.

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CF 2173D - Taiga's Carry Chains

Taiga is given a positive integer n and can perform exactly k moves. In each move, she chooses a power of two, 2^ℓ, and adds it to n. The score of each move is the number of binary carries that occur during the addition.

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CF 2173A - Sleeping Through Classes

We are asked to plan our sleep schedule across a sequence of classes, each of which is either important or not. The day is represented as a binary string where '1' marks an important class and '0' a non-important one.

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CF 2173B - Niko's Tactical Cards

We process a sequence of turns. The current score starts at 0. At turn i, we are given two possible transformations: If we take the red card, the new score becomes k - k - a[i] If we take the blue card, the new score becomes k - b[i] - k We must choose exactly one…

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CF 2173C - Kanade's Perfect Multiples

We are given a multiset of numbers, all lying in the range from 1 to a large limit k. From this array we must construct a set B of distinct integers, also between 1 and k, but under two simultaneous constraints that interact in a non-trivial way.