Codeforces Round 690 (Div. 3)

Solutions for Codeforces Round 690 (Div. 3) (contest 1462). 3/7 problems verified against sample I/O. Difficulty range: 800-1800.

7 items

Codeforces Round 690 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 3/7 | Rating range: 800-1800 | Time: 28m 5s

Problem Name Rating Tags Solve Time Verified
A Favorite Sequence 800 implementation, two-pointers 2m 19s ✗
B Last Year's Substring 800 dp, implementation, strings 3m 31s ✓
C Unique Number 900 brute-force, greedy, math 5m 17s ✗
D Add to Neighbour and Remove 1400 greedy, math, number-theory 1m 30s ✓
E1 Close Tuples (easy version) 1500 binary-search, combinatorics, math 8m 38s ✗
E2 Close Tuples (hard version) 1700 binary-search, combinatorics, implementation 1m 29s ✓
F The Treasure of The Segments 1800 binary-search, data-structures, greedy 5m 21s ✗
Practice › Codeforces Solutions › Codeforces Round 690 (Div. 3) ›

CF 1462E1 - Close Tuples (easy version)

We are given an array of integers where each element is between 1 and n, and we are asked to count the number of triples (i, j, z) such that the maximum value in the triple differs from the minimum by at most 2.
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CF 1462F - The Treasure of The Segments

We are given several independent test cases. In each test case, there is a collection of closed intervals on a number line. From this collection we want to keep as many intervals as possible, but only under a structural constraint.
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CF 1462E2 - Close Tuples (hard version)

We are asked to count specific subsets of an array where the elements are "close" to each other. More precisely, we have an array of integers a of length n, and we want the number of size-m tuples such that the difference between the largest and smallest element in the tuple…
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CF 1462C - Unique Number

We are given a target sum of digits, and we must construct the smallest positive integer whose digits are all different and whose digits add up exactly to that target. The output is not just any valid number, but the smallest one in standard decimal ordering.
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CF 1462D - Add to Neighbour and Remove

We are given an array of integers, and the goal is to make all elements equal using a specific operation any number of times. The operation allows picking an element and adding its value to one of its neighbors, then removing that element.
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Practice › Codeforces Solutions › Codeforces Round 690 (Div. 3) ›

CF 1462B - Last Year's Substring

The problem presents a string of digits and asks whether it can be transformed into the string "2020" using at most one contiguous deletion. Polycarp may remove zero or more consecutive characters anywhere in the string.
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Practice › Codeforces Solutions › Codeforces Round 690 (Div. 3) ›

CF 1462A - Favorite Sequence

Polycarp has a favorite sequence of integers, but we do not see it directly. Instead, we see the result of a special writing process he performs.
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