C++ Program to Find All Pairs Shortest Path
Posted by Superadmin on August 09 2022 07:08:09

C++ Program to Find All Pairs Shortest Path

This C++ Program to Find All Pairs Shortest Path in a Graph.

Here is source code of the C++ Program to Find All Pairs Shortest Path using Floyd’s Algorithm. The C++ program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C++ Program to Find All Pairs Shortest Path

```
 */
```
```
#include <iostream>
```
```
#include <cstdlib>
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```
#define max 10
```
```
#define infi 999
```
```
using namespace std;
```
```
int p[max][max];
```
```
/*
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 * All Pairs Shortest Path using Floyd's Algorithm

```
 */
```

void allpairshort(int a[max][max], int n)

```
{
```
```
    int k, i, j;
```
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    for (k = 0; k < n; k++)
```
```
    {
```
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        for (i = 0; i < n; i++)
```
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        {
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            for (j = 0; j < n; j++)
```
```
            {
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                if (a[i][k] + a[k][j] < a[i][j])

```
                {
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                    a[i][j] = a[i][k] + a[k][j];

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                    p[i][j] = k;
```
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                }
```
```
            }
```
```
        }
```
```
    }
```
```
}
```
```
 
```
```
/*
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 * Storing the shortest path
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```
 */
```
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void shortest(int i, int j)
```
```
{
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    int k = p[i][j];
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    if (k > 0)
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    {
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        shortest(i, k);
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        cout<<"  "<<k<<"  ";
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        shortest(k, j);
```
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    }
```
```
}
```
```
/*
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 * Display the Shortest Path
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```
 */
```

void findpath(int a[max][max], int i, int j, int n)

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{
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    cout<<"Path from " << i <<" to "<< j << ":";

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    if (a[i][j]  < infi)
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    {
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            cout<<"  "<<i<<"  ";
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            shortest(i, j);
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            cout<<"  "<<j<<" ";
```
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    }
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}
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/*
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 * Main Contains Menu
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 */
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int main()
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```
{
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```
    int i, j;
```

    int a[][10] =  {{0, 10, infi, 30, 100},

                {infi, 0 , 50, infi, infi},

                {infi, infi , 0, infi, 10},

                {infi, infi , 20, 0, 60},

                {infi, infi , infi, infi, 0},

```
                };
```
```
 
```
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    allpairshort(a, 5);
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    findpath(a, 0, 4, 5);
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    return 0;
```
```
}
```

$ g++ allpairshortestpath.cpp
$ a.out
Path from 0 to 4:  0    3    2    4
 
------------------
(program exited with code: 1)
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