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Competition Arena > MakingPairs

MakingPairs

2016 TCC India Online Round · 2016-03-24 · by IH19980412

2016 TCC India Online Round · 2016-03-24 · by IH19980412 · Brute Force
Class Name: MakingPairs
Return Type: int
Method Name: get
Arg Types: (vector<int>)
Problem Statement

Problem Statement

You have a collection of cards. Each card contains an integer between 0 and N-1, inclusive.

You are given a int[] card with N elements. For each valid i, you have exactly card[i] cards that contain the integer i.

You want to create pairs of cards that have the same number. Each card can only be used at most once. Return the largest number of pairs you can create.

Notes

  • The value of N is not given explicitly. You can determine its value by looking at the number of elements in card.

Constraints

  • N will be between 1 and 50, inclusive.
  • card will have exactly N elements.
  • Each element of card will be between 0 and 50, inclusive.
Examples
0)
{2,2,2}
Returns: 3

You have two cards with the number 0, two cards with the number 1, and two cards with the number 2. You can use these cards to form three pairs of identical cards: 0 with 0, 1 with 1, and 2 with 2.

1)
{1,1,1}
Returns: 0

Here, you have three cards that have the numbers 0, 1, and 2, respectively. As these cards are all distinct, you cannot make any pairs. Thus, the correct return value is 0.

2)
{5}
Returns: 2

You have five cards. Each of them contains the number 0. Using these cards, you can form at most two pairs of identical cards. (Note that you cannot use the same card in multiple pairs.)

3)
{43,23,10,39,39,22,22,0,3,4,3,2}
Returns: 102
4)
{0}
Returns: 0

Submissions are judged against all 59 archived test cases, of which 5 are shown here. Case numbers match the judge’s.

Coding Area

Language: C++17 · define a public class MakingPairs with a public method int get(vector<int> card) · 59 test cases · 2 s / 256 MB per case

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