- I am trying to solve the graph datastructure problem of hacker rank.
- My method should return the minimal cost of providing libraries to all.
- Providing my hacker rank question here https://www.hackerrank.com/challenges/torque-and-development/problem?h_l=interview&playlist_slugs%5B%5D%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D%5B%5D=graphs&isFullScreen=true
- I am planning to use BFS and solve the problem.
- so I read some articles and found this link https://medium.com/basecs/breaking-down-breadth-first-search-cebe696709d9
- but the problem is I am getting this error TypeError: Cannot read property 'left' of undefined
- I used the medium code.
- providing my code snippet below.
- can you tell me how to fix it.
'use strict';
const fs = require('fs');
process.stdin.resume();
process.stdin.setEncoding('utf-8');
let inputString = '';
let currentLine = 0;
process.stdin.on('data', inputStdin => {
inputString += inputStdin;
});
process.stdin.on('end', function() {
inputString = inputString.replace(/\s*$/, '')
.split('\n')
.map(str => str.replace(/\s*$/, ''));
main();
});
function readLine() {
return inputString[currentLine++];
}
// Complete the roadsAndLibraries function below.
function roadsAndLibraries(n, c_lib, c_road, cities) {
console.log("roadsAndLibraries n--->", n);
console.log("roadsAndLibraries c_lib--->", c_lib);
console.log("roadsAndLibraries c_road--->", c_road);
console.log("roadsAndLibraries cities--->", cities);
var m = new Map();
m.set('a', 2);
m.set('b', 3);
m.set('b', 3);
m.set('b', 2);
m.set('b', 1);
console.log("map value--->", m);
// Check that a root node exists.
// if (rootNode === null) {
// return;
// }
// Check that a root node exists.
if (n === null) {
console.log("n root node--->", n);
return;
}
// Create our queue and push our root node into it.
// var queue = [];
// queue.push(rootNode);
// Create our queue and push our root node into it.
var queue = [];
queue.push(n);
console.log(" queue.push--->", queue);
while (queue.length > 0) {
// Create a reference to currentNode, at the top of the queue.
var currentNode = queue[0];
// If currentNode has a left child node, add it to the queue.
if (currentNode.left !== null) {
queue.push(currentNode.left)
}
// If currentNode has a right child node, add it to the queue.
if (currentNode.right !== null) {
queue.push(currentNode.right)
}
// Remove the currentNode from the queue.
queue.shift()
}
}
function main() {
const ws = fs.createWriteStream(process.env.OUTPUT_PATH);
console.log("ws--->", ws);
const q = parseInt(readLine(), 10);
console.log("q--->", q);
for (let qItr = 0; qItr < q; qItr++) {
const nmC_libC_road = readLine().split(' ');
console.log("nmC_libC_road--->", nmC_libC_road);
const n = parseInt(nmC_libC_road[0], 10);
console.log("n--->", n);
const m = parseInt(nmC_libC_road[1], 10);
console.log("m--->", m);
const c_lib = parseInt(nmC_libC_road[2], 10);
console.log("c_lib--->", c_lib);
const c_road = parseInt(nmC_libC_road[3], 10);
console.log("c_road--->", c_road);
let cities = Array(m);
console.log("cities--->", cities);
for (let i = 0; i < m; i++) {
cities[i] = readLine().split(' ').map(citiesTemp => parseInt(citiesTemp, 10));
}
const result = roadsAndLibraries(n, c_lib, c_road, cities);
console.log("result--->", result);
ws.write(result + '\n');
}
ws.end();
}
after compilation
Input (stdin)Download
2
3 3 2 1
1 2
3 1
2 3
6 6 2 5
1 3
3 4
2 4
1 2
2 3
5 6
Your Output (stdout)
~ no response on stdout ~
Expected OutputDownload
4
12
Debug output
ws---> WriteStream {
_writableState:
WritableState {
objectMode: false,
highWaterMark: 16384,
finalCalled: false,
needDrain: false,
ending: false,
ended: false,
finished: false,
destroyed: false,
decodeStrings: true,
defaultEncoding: 'utf8',
length: 0,
writing: false,
corked: 0,
sync: true,
bufferProcessing: false,
onwrite: [Function: bound onwrite],
writecb: null,
writelen: 0,
bufferedRequest: null,
lastBufferedRequest: null,
pendingcb: 0,
prefinished: false,
errorEmitted: false,
emitClose: false,
bufferedRequestCount: 0,
corkedRequestsFree:
{ next: null,
entry: null,
finish: [Function: bound onCorkedFinish] } },
writable: true,
_events: [Object: null prototype] {},
_eventsCount: 0,
_maxListeners: undefined,
path:
'/tmp/submission/20190702/20/31/hackerrank-d27db21d31abaff7353d49d7e433da3a/0.userout',
fd: null,
flags: 'w',
mode: 438,
start: undefined,
autoClose: true,
pos: undefined,
bytesWritten: 0,
closed: false }
q---> 2
nmC_libC_road---> [ '3', '3', '2', '1' ]
n---> 3
m---> 3
c_lib---> 2
c_road---> 1
cities---> [ <3 empty items> ]
roadsAndLibraries n---> 3
roadsAndLibraries c_lib---> 2
roadsAndLibraries c_road---> 1
roadsAndLibraries cities---> [ [ 1, 2 ], [ 3, 1 ], [ 2, 3 ] ]
map value---> Map { 'a' => 2, 'b' => 1 }
queue.push---> [ 3 ]
