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Janardhan Pulivarthi
Janardhan Pulivarthi

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Day 15 of 100 - Java: Graph data structure

Graph data structure with Java

 class Graph { class Edge { int src, dest; } // Number of vertices and edges int vertices, edges; Edge[] edge; Graph(int vertices, int edges) { this.vertices = vertices; this.edges = edges; edge = new Edge[edges]; for (int i = 0; i < edges; i++) { edge[i] = new Edge(); } } public static void main(String[] args) { int numVertices = 5; int numEdges = 7; Graph g = new Graph(numVertices, numEdges); g.edge[0].src = 1; g.edge[0].dest = 2; g.edge[1].src = 1; g.edge[1].dest = 3; g.edge[2].src = 1; g.edge[2].dest = 4; g.edge[3].src = 2; g.edge[3].dest = 3; g.edge[4].src = 2; g.edge[4].dest = 4; g.edge[5].src = 3; g.edge[5].dest = 5; g.edge[6].src = 4; g.edge[6].dest = 5; for (int i = 0; i < numEdges; i++) { System.out.println(g.edge[i].src + " - " + g.edge[i].dest); } } }
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https://github.com/j143/java-graph-datastructure-example

Java Collections conversions

Java List or ArrayList to Array

ArrayList homekeys = new ArrayList<> (); homekeys.add("A"); homekeys.add("S"); homekeys.add("D"); homekeys.add("F"); // Create new Array String[] homekeysArray = new String[homekeys.size()]; homekeys.toArray(homekeysArray);
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But, the other way around is simple

// import java.util.Arrays; String[] array = {"A", "S", "D", "F"}; List languages = new ArrayList<> (Arrays.asList(array))
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Based on the above learning I have solved https://leetcode.com/problems/rearrange-array-elements-by-sign/ but got Time Limit Exceeded.

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