Given an array of names of candidates in an election. A candidate name in array represents a vote casted to the candidate. Print the name of candidates received Max vote. If there is tie, print lexicographically smaller name.
Examples:
Input : votes[] = {"john", "johnny", "jackie",
"johnny", "john", "jackie",
"jamie", "jamie", "john",
"johnny", "jamie", "johnny",
"john"};
Output : John
We have four Candidates with name as 'John',
'Johnny', 'jamie', 'jackie'. The candidates
John and Johny get maximum votes. Since John
is alphabetically smaller, we print it.
A simple solution is to run two loops and count occurrences of every word. Time complexity of this solution is O(n * n * MAX_WORD_LEN).
An efficient solution is to use Hashing. We insert all votes in a hash map and keep track of counts of different names. Finally we traverse the map and print the person with maximum votes.
CPP
// C++++ program to find winner in an election. #include "bits/stdc++.h" using namespace std; /* We have four Candidates with name as 'John', 'Johnny', 'jamie', 'jackie'. The votes in String array are as per the votes casted. Print the name of candidates received Max vote. */ void findWinner(vector<string>& votes) { // Insert all votes in a hashmap map<string,int> mapObj ; for (auto& str : votes) { mapObj[str]++; } // Traverse through map to find the candidate // with maximum votes. int maxValueInMap = 0; string winner; for (auto& entry : mapObj) { string key = entry.first; int val = entry.second; if (val > maxValueInMap) { maxValueInMap = val; winner = key; } // If there is a tie, pick lexicographically // smaller. else if (val == maxValueInMap && winner>key) winner = key; } cout << winner << endl; } // Driver code int main() { vector<string> votes = { "john", "johnny", "jackie", "johnny", "john", "jackie", "jamie", "jamie", "john", "johnny", "jamie", "johnny", "john" }; findWinner(votes); return 0; } |
Java
// Java program to find winner in an election. import java.util.*; public class ElectoralVotingBallot { /* We have four Candidates with name as 'John', 'Johnny', 'jamie', 'jackie'. The votes in String array are as per the votes casted. Print the name of candidates received Max vote. */ public static void findWinner(String votes[]) { // Insert all votes in a hashmap Map<String,Integer> map = new HashMap<String, Integer>(); for (String str : votes) { if (map.keySet().contains(str)) map.put(str, map.get(str) + 1); else map.put(str, 1); } // Traverse through map to find the candidate // with maximum votes. int maxValueInMap = 0; String winner = ""; for (Map.Entry<String,Integer> entry : map.entrySet()) { String key = entry.getKey(); Integer val = entry.getValue(); if (val > maxValueInMap) { maxValueInMap = val; winner = key; } // If there is a tie, pick lexicographically // smaller. else if (val == maxValueInMap && winner.compareTo(key) > 0) winner = key; } System.out.println(winner); } // Driver code public static void main(String[] args) { String[] votes = { "john", "johnny", "jackie", "johnny", "john", "jackie", "jamie", "jamie", "john", "johnny", "jamie", "johnny", "john" }; findWinner(votes); } } |
C#
// C# program to find winner in an election. using System; using System.Collections.Generic; public class ElectoralVotingBallot { /* We have four Candidates with name as 'John', 'Johnny', 'jamie', 'jackie'. The votes in String array are as per the votes casted. Print the name of candidates received Max vote. */ public static void findWinner(String []votes) { // Insert all votes in a hashmap Dictionary<String,int> map = new Dictionary<String, int>(); foreach (String str in votes) { if (map.ContainsKey(str)) map[str] = map[str] + 1; else map.Add(str, 1); } // Traverse through map to find the candidate // with maximum votes. int maxValueInMap = 0; String winner = ""; foreach(KeyValuePair<String, int> entry in map) { String key = entry.Key; int val = entry.Value; if (val > maxValueInMap) { maxValueInMap = val; winner = key; } // If there is a tie, pick lexicographically // smaller. else if (val == maxValueInMap && winner.CompareTo(key) > 0) winner = key; } Console.WriteLine(winner); } // Driver code public static void Main(String[] args) { String[] votes = { "john", "johnny", "jackie", "johnny", "john", "jackie", "jamie", "jamie", "john", "johnny", "jamie", "johnny", "john" }; findWinner(votes); } } // This code is contributed by PrinciRaj1992 |
Output:
John
Another efficient solution is to use Trie. Please refer most frequent word in an array of strings.
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