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GraphQuesPart3
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@riyakushwaha
riyakushwaha committed Jan 3, 2021
1 parent 009e8f6 commit 41441b1
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147 changes: 147 additions & 0 deletions MultiSolver.java
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/*
Name: Multisolver - Smallest, Longest, Ceil, Floor, Kthlargest Path
Source: PepCoding
Link: https://www.pepcoding.com/resources/online-java-foundation/graphs/mutilsovler-graph-official/ojquestion
Statement: You are required to find and print the values of
1 Smallest path and it's weight separated by an "@"
2 Largest path and it's weight separated by an "@"
3 Just Larger path (than criteria in terms of weight) and it's weight separated by an "@"
4 Just smaller path (than criteria in terms of weight) and it's weight separated by an "@"
5 Kth largest path and it's weight separated by an "@"
*/

import java.io.*;
import java.util.*;

public class MultiSolver {
static class Edge {
int src;
int nbr;
int wt;

Edge(int src, int nbr, int wt) {
this.src = src;
this.nbr = nbr;
this.wt = wt;
}
}

static class Pair implements Comparable < Pair > {
int wsf;
String psf;

Pair(int wsf, String psf) {
this.wsf = wsf;
this.psf = psf;
}

public int compareTo(Pair o) {
return this.wsf - o.wsf;
}
}

public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

int vtces = Integer.parseInt(br.readLine());
ArrayList < Edge > [] graph = new ArrayList[vtces];
for (int i = 0; i < vtces; i++) {
graph[i] = new ArrayList < > ();
}

int edges = Integer.parseInt(br.readLine());
for (int i = 0; i < edges; i++) {
String[] parts = br.readLine().split(" ");
int v1 = Integer.parseInt(parts[0]);
int v2 = Integer.parseInt(parts[1]);
int wt = Integer.parseInt(parts[2]);
graph[v1].add(new Edge(v1, v2, wt));
graph[v2].add(new Edge(v2, v1, wt));
}

int src = Integer.parseInt(br.readLine());
int dest = Integer.parseInt(br.readLine());

int criteria = Integer.parseInt(br.readLine());
int k = Integer.parseInt(br.readLine());

boolean[] visited = new boolean[vtces];
multisolver(graph, src, dest, visited, criteria, k, src + "", 0);

System.out.println("Smallest Path = " + spath + "@" + spathwt);
System.out.println("Largest Path = " + lpath + "@" + lpathwt);
System.out.println("Just Larger Path than " + criteria + " = " + cpath + "@" + cpathwt);
System.out.println("Just Smaller Path than " + criteria + " = " + fpath + "@" + fpathwt);
System.out.println(k + "th largest path = " + pq.peek().psf + "@" + pq.peek().wsf);
}



static String spath;
static Integer spathwt = Integer.MAX_VALUE;
static String lpath;
static Integer lpathwt = Integer.MIN_VALUE;
static String cpath;
static Integer cpathwt = Integer.MAX_VALUE;
static String fpath;
static Integer fpathwt = Integer.MIN_VALUE;
static PriorityQueue < Pair > pq = new PriorityQueue < > ();
public static void multisolver(ArrayList < Edge > [] graph, int src, int dest, boolean[] visited, int criteria, int k, String psf, int wsf) {

if(src == dest)
{
if(spathwt > wsf)
{
spathwt = wsf;
spath = psf;
}

if(lpathwt < wsf)
{
lpathwt = wsf;
lpath = psf;
}

if(wsf > criteria && wsf < cpathwt)
{
cpathwt = wsf;
cpath = psf;
}

if(wsf < criteria && wsf > fpathwt)
{
fpathwt = wsf;
fpath = psf;
}

if(pq.size() < k)
{
pq.add(new Pair(wsf, psf));
}
else
{
if(pq.peek().wsf < wsf)
{
pq.remove();
pq.add(new Pair(wsf, psf));
}
}

return;
}

visited[src] = true;

for( Edge edge : graph[src])
{
if(!visited[edge.nbr])
{
multisolver(graph, edge.nbr, dest, visited, criteria, k, psf +edge.nbr , wsf + edge.wt);
}
}

visited[src] = false;

}

}
89 changes: 89 additions & 0 deletions PerfectFriends.java
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/*
Name: Perfect Friends
Source: PepCoding
Link: https://www.pepcoding.com/resources/online-java-foundation/graphs/perfect-friends-official/ojquestion
Statement: You are given a number n (representing the number of students). Each student will have an id
from 0 to n - 1. You are given a number k (representing the number of clubs). In the next k lines, two numbers are given separated by a space. The numbers are ids of
students belonging to same club. You have to find in how many ways can we select a pair of students such that both students are from different clubs.
*/

import java.io.*;
import java.util.*;

public class PerfectFriends {

public static class Edge {
int src;
int nbr;

Edge(int src, int nbr)
{
this.src = src;
this.nbr = nbr;
}
}

public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

int n = Integer.parseInt(br.readLine());
int k = Integer.parseInt(br.readLine());
ArrayList < Edge > [] graph = new ArrayList[n];

for(int i=0; i<n; i++)
{
graph[i] = new ArrayList<>();
}

for(int i=0; i<k; i++)
{
String [] parts = br.readLine().split(" ");
int a = Integer.parseInt(parts[0]);
int b = Integer.parseInt(parts[1]);
graph[a].add(new Edge(a, b));
graph[b].add(new Edge(b, a));
}

ArrayList < ArrayList < Integer >> comps = new ArrayList < > ();



boolean [] visited = new boolean[n];

for(int i=0; i<n; i++)
{
if(!visited[i])
{
ArrayList<Integer> comp = new ArrayList<>();
perfectFriends(graph, i, comp, visited);
comps.add(comp);
}
}

int count =0;
for(int i=0; i<comps.size(); i++)
{
for(int j=i+1; j<comps.size(); j++)
{
count+= (comps.get(i).size() * comps.get(j).size());
}
}

System.out.println(count);

}

public static void perfectFriends(ArrayList < Edge > [] graph , int src, ArrayList<Integer> comp,boolean [] visited){

visited[src] = true;
comp.add(src);

for(Edge edge: graph[src])
{
if(!visited[edge.nbr])
{
perfectFriends(graph, edge.nbr, comp, visited);
}
}
}
}
102 changes: 102 additions & 0 deletions PrimsAlgo.java
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/*
Name: Minimum Wire Required To Connect All Pcs (Prim')s Algo
Source: PepCoding
Link: https://www.pepcoding.com/resources/online-java-foundation/graphs/minimum-wire-to-connect-all-pcs-official/ojquestion
Statement: You are given a graph and a source vertex. The vertices represent computers and the edges
represent length of LAN wire required to connect them. You are required to find the minimum length of wire required to connect all PCs over a network.
Print the output in terms of which all PCs need to be connected, and the length of wire between them.
*/

import java.io.*;
import java.util.*;

public class PrimsAlgo {
static class Edge {
int src;
int nbr;
int wt;

Edge(int src, int nbr, int wt) {
this.src = src;
this.nbr = nbr;
this.wt = wt;
}
}

public static class Pair implements Comparable<Pair>
{
int vtx;
int src;
int wt;

Pair(int vtx, int src, int wt)
{
this.vtx = vtx;
this.src = src;
this.wt = wt;
}

public int compareTo(Pair oth)
{
return this.wt - oth.wt;
}

}

public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

int vtces = Integer.parseInt(br.readLine());
ArrayList < Edge > [] graph = new ArrayList[vtces];
for (int i = 0; i < vtces; i++) {
graph[i] = new ArrayList < > ();
}

int edges = Integer.parseInt(br.readLine());
for (int i = 0; i < edges; i++) {
String[] parts = br.readLine().split(" ");
int v1 = Integer.parseInt(parts[0]);
int v2 = Integer.parseInt(parts[1]);
int wt = Integer.parseInt(parts[2]);
graph[v1].add(new Edge(v1, v2, wt));
graph[v2].add(new Edge(v2, v1, wt));
}

boolean [] visited = new boolean[vtces];
PriorityQueue<Pair> que = new PriorityQueue<>();
que.add(new Pair(0, -1, 0));

while(que.size() > 0)
{
Pair top = que.remove();

if(visited[top.vtx])
{
continue;
}

visited[top.vtx] = true;

if(top.src > -1)
{
System.out.println("[" + top.vtx + "-" + top.src + "@" + top.wt + "]");
}

for(Edge edge: graph[top.vtx])
{
if(!visited[edge.nbr])
{
que.add(new Pair(edge.nbr, edge.src, edge.wt));
}

}


}




}

}

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