Hacker Rank: Breadth First Search: Shortest Reach

//Enter your code here. Read input from STDIN. Print output to STDOUT//
//  main.m
//  Breadth First Search: Shortest Reach
//
//  Created by Nathan Arnold on 11/1/15.
//  Copyright © 2015 Nathan Arnold. All rights reserved.
//

#import <Foundation/Foundation.h>

static int EDGE_LENGTH = 6;

NSMutableDictionary *hasVisited;
NSMutableDictionary *distanceFromRoot;


/*
 Breadth-First-Search(G, v):
 2
 3     for each node n in G:
 4         n.distance = INFINITY
 5         n.parent = NIL
 6
 7     create empty queue Q
 8
 9     v.distance = 0
 10     Q.enqueue(v)
 11
 12     while Q is not empty:
 13
 14         u = Q.dequeue()
 15
 16         for each node n that is adjacent to u:
 17             if n.distance == INFINITY:
 18                 n.distance = u.distance + 1
 19                 n.parent = u
 20                 Q.enqueue(n)
 */



void breadthFirstSearch(NSDictionary *graph, NSNumber *start, int numberOfNodes){
    
    NSMutableArray *queue = [NSMutableArray arrayWithCapacity:numberOfNodes];
    [queue addObject:start];
    while ([queue count]){
        
        NSNumber *currentNode = [queue firstObject];
        [queue removeObjectAtIndex:0];
        
        NSSet *children = graph[currentNode];
        
        long length = [distanceFromRoot[currentNode] longValue];
        
        [children enumerateObjectsUsingBlock:^(id obj, BOOL * stop) {
            
            NSNumber *cachedDistance = distanceFromRoot[obj];
            
            if (!cachedDistance) {
                distanceFromRoot[obj] = [NSNumber numberWithLong:(length + 1)];
                [queue addObject:obj];
            }
        }];
    }
}

void processTestCase() {
    
    int nodes = 0;
    int edges = 0;
    int start = 0;
    
    scanf("%d %d", &nodes, &edges);
    
    //key is nodeID, value is set of nodeIDs connected to node
    NSMutableDictionary *graph = [NSMutableDictionary dictionaryWithCapacity:nodes];
    
    
    //Build the graph
    
    for (int i = 0; i < edges; i++){
        
        int node1 = 0;
        int node2 = 0;
        
        scanf("%d %d",&node1, &node2);
        
        NSNumber *num1 =[NSNumber numberWithInt:node1];
        NSNumber *num2 =[NSNumber numberWithInt:node2];
        
        NSMutableSet *set1 = graph[num1];
        NSMutableSet *set2 = graph[num2];
        
        if (set1) {
            [set1 addObject:num2];
        } else {
            graph[num1] = [NSMutableSet setWithObjects:num2, nil];
        }
        
        if (set2) {
            [set2 addObject:num1];
        } else {
            graph[num2] = [NSMutableSet setWithObjects:num1, nil];
        }
    }
    
    scanf("%d", &start);
    

    hasVisited = [NSMutableDictionary dictionaryWithCapacity:nodes];
    distanceFromRoot = [NSMutableDictionary dictionaryWithCapacity:nodes];

    breadthFirstSearch(graph, [NSNumber numberWithInt:start], nodes);
    
    for (int i = 1; i <= nodes; i++) {
        
        if (start != i) {
            
            NSNumber *node = [NSNumber numberWithInt:i];
            
            if (distanceFromRoot[node]){
                printf("%d ",[distanceFromRoot[node] intValue] * EDGE_LENGTH);
            } else {
                printf("-1 ");
            }
        }
    }
    
    printf("\n");
    
}


int main(int argc, const char * argv[]) {
    // @autoreleasepool {
    // insert code here...
    
    int numberOfTestCases = 0;
    scanf("%d", &numberOfTestCases);
    
    for (int i = 0; i < numberOfTestCases; i++){
        processTestCase();
    }
    //  }
    
    return 0;
}