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miku

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Wander_Lust
2026-05-19 07:04:53 +05:30
parent 825e915f5f
commit 5beeb7c652
5 changed files with 254 additions and 0 deletions
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Nqueens.java
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import java.util.*;
public class Nqueens{
static int n;
static int[][] board;
static boolean isSafe(int r, int c){
for(int i=0;i<r;i++){
if(board[i][c]==1)
return false;
}
for(int i=r,j=c;i>=0 && j>=0;i--,j--){
if(board[i][j]==1)
return false;
}
for(int i=r,j=c;i>=0 && j<n;i--,j++){
if(board[i][j]==1)
return false;
}
return true;
}
static void solve(int r){
if(r==n){
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
if(board[i][j]==1){
System.out.print(" Q ");
}else
System.out.print(" . ");
}
System.out.println();
}
System.out.println();
return;
}
for(int i=0;i<n;i++){
if(isSafe(r,i)){
board[r][i] =1;
solve(r+1);
board[r][i]=0;
}
}
}
public static void main(String[] args){
Scanner sc= new Scanner(System.in);
System.out.print("\nEnter n: ");
n =sc.nextInt();
board = new int[n][n];
solve(0);
sc.close();
}
}
bellmanFord.java
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import java.util.*;
public class bellmanFord{
static class Edge{
int src, dest, weigh;
Edge(int s, int d, int w){
src = s;
dest = d;
weigh = w;
}
}
static void printPath(int vertex, int[] parent){
if(vertex==-1) return;
printPath(parent[vertex], parent);
System.out.print(vertex+" ");
}
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.print("Enter no. of vertices and edges: ");
int n = sc.nextInt();
int e = sc.nextInt();
int[] parent = new int[n];
Edge[] edges = new Edge[e];
int[] dist = new int[n];
System.out.print("Enter the edges(src dest weight): ");
for(int i=0;i<e;i++){
int s = sc.nextInt();
int d = sc.nextInt();
int w = sc.nextInt();
edges[i] = new Edge(s,d,w);
}
System.out.println("\nEnter source vertex: ");
int s = sc.nextInt();
for(int i=0;i<n;i++){
dist[i] = 999;
parent[i] = -1;
}
dist[s] = 0;
for(int i=1;i<=n-1;i++){
for(int j=0;j<e;j++){
int sr = edges[j].src;
int d = edges[j].dest;
int w = edges[j].weigh;
if(dist[sr]!=999 && dist[sr] + w < dist[d]){
dist[d] = dist[sr]+w;
parent[d] = sr;
}
}
}
boolean negcycle = false;
for(int j=0;j<e;j++){
int sr = edges[j].src;
int d = edges[j].dest;
int w = edges[j].weigh;
if(dist[sr]!=999 && dist[sr] + w < dist[d]){
dist[d] = dist[sr]+w;
negcycle = true;
break;
}
}
if(negcycle){
System.out.println("\nNegative cycle exists.");
}else{
System.out.println("\nShortest paths from source vertex " + s + ":\n");
for(int i=0;i<n;i++){
System.out.println("vertex: "+i);
System.out.println("Cost: "+ dist[i]);
System.out.println("Path: ");
printPath(i, parent);
System.out.println();
}
}
sc.close();
}
}
dijkstra.java
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import java.util.*;
public class dijkstra{
static int V;
static int minDistance(int[] dist, boolean[] visited){
int min = Integer.MAX_VALUE;
int minIndex = -1;
for(int v=0;v<V;v++){
if(!visited[v] && dist[v]<min){
min = dist[v];
minIndex = v;;
}
}
return minIndex;
}
static void printPath(int vertex, int[] parent){
if(vertex==-1) return;
printPath(parent[vertex], parent);
System.out.print(vertex+" ");
}
static void dijkstra(int[][] graph, int source){
int[] dist = new int[V];
boolean[] visited = new boolean[V];
int[] parent = new int[V];
Arrays.fill(dist, Integer.MAX_VALUE);
for(int i=0;i<V;i++)
parent[i] = -1;
dist[source] = 0;
long start = System.nanoTime();
for(int count=0;count<V-1;count++){
int u = minDistance(dist, visited);
visited[u] = true;
for(int v=0;v<V;v++){
if(!visited[v] && graph[u][v]!=0 && dist[u]!=Integer.MAX_VALUE && dist[u]+graph[u][v]<dist[v]){
dist[v] = dist[u]+graph[u][v];
parent[v] = u;
}
}
}
long end = System.nanoTime();
System.out.println("\nSHortest distances from source "+source+":");
for(int i =0;i<V;i++){
System.out.println("Vetex: "+i);
System.out.println("Cost: "+dist[i]);
System.out.println("Path: ");
printPath(i, parent);
System.out.println("\n");
}
long executionTime = end - start;
System.out.println("Execution Time: " + executionTime + " nanoseconds");
}
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("\nENter number of vertices: ");
V = sc.nextInt();
int[][] graph = new int[V][V];
System.out.println("ENter adjacency matrix: ");
for(int i=0;i<V;i++){
for(int j =0;j<V;j++){
graph[i][j] =sc.nextInt();
}
}
int source = 0;
dijkstra(graph, source);
sc.close();
}
}
kruskalMST$Edge.class
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subsetSum.java
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import java.util.*;
public class subsetSum{
static boolean found = false;
static int[] arr;
static int target;
static ArrayList<Integer> current= new ArrayList<>();
static void subset(int index, int sum, ArrayList<Integer> current){
if(sum==target){
found = true;
System.out.println("\nSubset found: "+current);
return;
}
if(arr.length == index || sum>target){
return;
}
current.add(arr[index]);
subset(index+1, sum+arr[index], current);
current.remove(current.size()-1);
subset(index+1, sum, current);
}
public static void main(String[] args){
Scanner sc= new Scanner(System.in);
System.out.println("\nEnter size of array: ");
int n = sc.nextInt();
arr = new int[n];
System.out.println("\nENter array elements: ");
for(int i=0;i<n;i++)
arr[i] = sc.nextInt();
System.out.print("Enter target: ");
target = sc.nextInt();
subset(0,0,new ArrayList<Integer>());
if(!found){
System.out.println("\nNo subset found");
}
sc.close();
}
}