Problem Summary

Given M types of coins in infinite quantities where the value of each type of coin is given in array C, determine the number of ways to make change for N units using these coins.

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Problem Summary

Given an array A with N integers between 3500 and 4500, find the number of unique multisets that can be formed using elements from the array such that the bitwise XOR of all the elements of the multiset is a prime number.

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Problem Summary

Given two strings, A and B, determine if it is possible that B is an abbreviation for A.

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Problem Summary

Given a tree with N nodes, find the number of ways to divide the nodes into two sets, such that every node has at least one node that is connected to it and in the same set with it.

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Problem Summary

Given an array B of N positive integers, and the relationship between array A and B: 1 ≤ A[i] ≤ B[i] (1 ≤ i ≤ N), find the maximum of S = sum{|A[i] - A[i-1]|}, 2 ≤ i ≤ N.

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Problem Summary

Given a map with N shopping centers and M bidirectional roads. Each road connects two distinct shopping centers and has a travel time. There are K different kinds of fish sold in these centers, and each center may have different kinds of fish.

Two cats travel from center 1 to center N, and they want to collectively purchase all K types of fish in a minimal amount of time. Any purchase costs no time. Their paths are not necessarily the same. The total shopping time is the maximum of two cats’ shopping times. Find the minimal total shopping time.
(2 ≤ N ≤ 1000 , 1 ≤ M ≤ 2000 , 0 ≤ K ≤ 10)

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Problem Summary

Given a time in 12-hour AM/PM format, convert it to 24-hour time.

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Problem Summary

Given a map of N cities with M bidirectional roads, along with the cost to repair a road and the cost to build a new library, find the minimal cost to build some libraries and repair some roads such that every city would have access to at least one library.

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Problem Summary

Given prices of a house in N years, find the minimum loss if we first buy it and then sell it at a lower price.

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Problem Summary

Alice and Bob play a game.

Given a tree with N nodes, two integers G and K, and G guesses (u1,v1),…,(ug,vg). (1<=N,G,K<=100000)

(ui,vi) means Alice guesses that ui is the parent of vi.

When a node of the tree is randomly selected (with equal probability) to be root by Bob, and Alice does not know, find the probability that the number of right guesses is greater than or equal to K.

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