HackerRank•May 19, 2025

Minimum Distances

Hazrat Ali

HackerRank

The distance between two array values is the number of indices between them. Given , find the minimum distance between any pair of equal elements in the array. If no such value exists, return .

Example

There are two matching pairs of values:  and . The indices of the 's are  and , so their distance is . The indices of the 's are  and , so their distance is . The minimum distance is .

Function Description

Complete the minimumDistances function in the editor below.

minimumDistances has the following parameter(s):

  • int a[n]: an array of integers

Returns

  • int: the minimum distance found or  if there are no matching elements

Input Format

The first line contains an integer , the size of array .
The second line contains  space-separated integers .

Constraints

Output Format

Print a single integer denoting the minimum  in . If no such value exists, print .

Sample Input

STDIN           Function
-----           --------
6               arr[] size n = 6
7 1 3 4 1 7     arr = [7, 1, 3, 4, 1, 7]

Sample Output

3


Solution
#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector<string> split(const string &);

/*
 * Complete the 'minimumDistances' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts INTEGER_ARRAY a as parameter.
 */

// Complete the minimumDistances function below.
int minimumDistances(vector<int> a) {
    map<int, pair<int, int>> m;
    int minimum = INT_MAX;
    for (unsigned long i = 0; i < a.size(); i++) {
        if (m.find(a[i]) == m.end()) {
            m.insert({ a[i], {i, INT_MAX} });
        }
        else {
            int first = get<0>(m[a[i]]);
            int second = get<1>(m[a[i]]);
            if (second == INT_MAX) {
                second = i;
                if (i - first < minimum)
                    minimum = i - first;
            }
            else {
                int new_diff = i - second;
                if (second - first > new_diff) {
                    first = second;
                    second = i;
                    if (new_diff < minimum)
                        minimum = new_diff;
                }
            }
        }
    }

    if (minimum == INT_MAX) return -1;
    else return minimum;
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string n_temp;
    getline(cin, n_temp);

    int n = stoi(ltrim(rtrim(n_temp)));

    string a_temp_temp;
    getline(cin, a_temp_temp);

    vector<string> a_temp = split(rtrim(a_temp_temp));

    vector<int> a(n);

    for (int i = 0; i < n; i++) {
        int a_item = stoi(a_temp[i]);

        a[i] = a_item;
    }

    int result = minimumDistances(a);

    fout << result << "\n";

    fout.close();

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}

vector<string> split(const string &str) {
    vector<string> tokens;

    string::size_type start = 0;
    string::size_type end = 0;

    while ((end = str.find(" ", start)) != string::npos) {
        tokens.push_back(str.substr(start, end - start));

        start = end + 1;
    }

    tokens.push_back(str.substr(start));

    return tokens;
}




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