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by Sumit Chourasia | Jun 13, 2020 | Category :coding | Tags : c-sharparrayडेटा-संरचनाleetcodeआसानalgorithm

Distance Between Bus Stops - Array - Easy - LeetCode - मिनी टीवी

A bus has n stops numbered from 0 to n - 1 that form a circle. We know the distance between all pairs of neighboring stops where distance[i] is the distance between the stops number i and (i + 1) % n.

The bus goes along both directions i.e. clockwise and counterclockwise.

Return the shortest distance between the given start and destination stops.

Example 1:

Input: distance = [1,2,3,4], start = 0, destination = 1

Output: 1

Explanation: Distance between 0 and 1 is 1 or 9, minimum is 1.

Example 2:

Input: distance = [1,2,3,4], start = 0, destination = 2

Output: 3

Explanation: Distance between 0 and 2 is 3 or 7, minimum is 3.

Example 3:

Input: distance = [1,2,3,4], start = 0, destination = 3

Output: 4

Explanation: Distance between 0 and 3 is 6 or 4, the minimum is 4.

Constraints:

1 <= n <= 10^4

distance.length == n

0 <= start, destination < n

0 <= distance[i] <= 10^4

Solution:

``````using System;
using System.Collections.Generic;
using System.Text;

{
public class DistanceBetweenBusStopsSoln
{
public int DistanceBetweenBusStops(int[] distance, int start, int destination)
{
var clockwise = 0;
bool clockwiseFound = false;

var antiClockwise = 0;
bool antiClockwiseFound = false;
int i = start;
int j = start;

while (true)
{
i++;
j--;

if (i > distance.Length - 1)
{
i = 0;
}

if (j < 0)
{
j = distance.Length - 1;
}

if (i == destination)
{
if ((i - 1) < 0)
{
clockwise += distance[distance.Length - 1];
}
else
{
clockwise += distance[i - 1];
}
clockwiseFound = true;
}

if( j == destination)
{
antiClockwise += distance[j];
antiClockwiseFound = true;
}

if (!clockwiseFound)
{
if ((i - 1) < 0)
{
clockwise += distance[distance.Length - 1];
}
else
{
clockwise += distance[i - 1];
}
}

if (!antiClockwiseFound)
{
antiClockwise += distance[j];
}

if(clockwiseFound && antiClockwiseFound)
{
break;
}
}

return clockwise < antiClockwise ? clockwise : antiClockwise;
}
}
}
``````

Time Complexity: O(n)

Space Complexity: O(1)

Unit Tests:

``````using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.Array
{
[TestClass]
public class DistanceBetweenBusStopsSolnTests
{
[TestMethod]
public void DistanceBetweenBusStopsSoln_First()
{
var distance = new int[] { 1, 2, 3, 4 };
var start = 0;
var destination = 1;

var output = 1;

var res = new DistanceBetweenBusStopsSoln().DistanceBetweenBusStops(distance, start, destination);

Assert.AreEqual(output, res);
}

[TestMethod]
public void DistanceBetweenBusStopsSoln_Second()
{
var distance = new int[] { 1, 2, 3, 4 };
var start = 0;
var destination = 2;

var output = 3;

var res = new DistanceBetweenBusStopsSoln().DistanceBetweenBusStops(distance, start, destination);

Assert.AreEqual(output, res);
}

[TestMethod]
public void DistanceBetweenBusStopsSoln_Third()
{
var distance = new int[] { 1, 2, 3, 4 };
var start = 0;
var destination = 3;

var output = 4;

var res = new DistanceBetweenBusStopsSoln().DistanceBetweenBusStops(distance, start, destination);

Assert.AreEqual(output, res);
}

[TestMethod]
public void DistanceBetweenBusStopsSoln_Fourt()
{
var distance = new int[] { 7, 10, 1, 12, 11, 14, 5, 0 };
var start = 7;
var destination = 2;

var output = 17;

var res = new DistanceBetweenBusStopsSoln().DistanceBetweenBusStops(distance, start, destination);

Assert.AreEqual(output, res);
}

[TestMethod]
public void DistanceBetweenBusStopsSoln_Fifth()
{
var distance = new int[] { 3, 6, 7, 2, 9, 10, 7, 16, 11 };
var start = 6;
var destination = 2;

var output = 28;

var res = new DistanceBetweenBusStopsSoln().DistanceBetweenBusStops(distance, start, destination);

Assert.AreEqual(output, res);
}

[TestMethod]
public void DistanceBetweenBusStopsSoln_Sixth()
{
var distance = new int[] { 14, 13, 4, 7, 10, 17, 8, 3, 2, 13 };
var start = 2;
var destination = 9;

var output = 40;

var res = new DistanceBetweenBusStopsSoln().DistanceBetweenBusStops(distance, start, destination);

Assert.AreEqual(output, res);
}
}
}
``````

Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia