Djikstra algorithm in php

djikstra.php

<?php

/**
 * Djikstra algorithm in php
 * 
 * Input data from STDIN as:
 * 
 * 4 8
 * 1 2 6
 * 1 3 2
 * 1 4 10
 * 2 4 4
 * 3 1 5
 * 3 2 3
 * 3 4 8
 * 4 2 1
 * 1 4
 * Answer: 9
 * 
 * 5 4
 * 1 2 1
 * 2 3 1
 * 3 4 1
 * 4 5 1
 * 1 5
 * Answer: 4
 * 
 * In case of no path - output -1
 */
function djikstra()
{
    // Number of vertexes and edges
    list($vertexCount, $edgesCount) = explode(' ', trim(fgets(STDIN)));
    $totalDistancesToV = array_fill_keys(range(1, $vertexCount), INF);
    $notCheckedV = array_fill_keys(range(1, $vertexCount), 1);

    // Distance between vertexes
    $distances = [];
    while ($edgesCount--) {
        list($from, $to, $distance) = explode(' ', trim(fgets(STDIN)));
        if (empty($distances[$from])) {
            $distances[$from] = [];
        }
        $distances[$from][$to] = (int)$distance;
    }

    // Start end vertexes to find distance between
    list($searchFrom, $searchTo) = explode(' ', trim(fgets(STDIN)));
    $searchFrom = (int)$searchFrom;

    $totalDistancesToV[$searchFrom] = 0;
    while (true) {
        if (!empty($distances[$searchFrom])) {
            foreach ($distances[$searchFrom] as $vertex => $distance) {
                $totalDistancesToV[$vertex] = min(
                    $totalDistancesToV[$vertex],
                    $totalDistancesToV[$searchFrom] + $distance
                );
            }
        }

        unset($notCheckedV[$searchFrom]);

        if ($notCheckedV) {
            $minDistance = false;
            foreach	($notCheckedV as $vertex => $v) {
                if (false === $minDistance || $totalDistancesToV[$vertex] < $minDistance) {
                    $searchFrom = $vertex;
                    $minDistance = $totalDistancesToV[$vertex];
                }
            }
        } else {
            break;
        }
    }

    echo ($totalDistancesToV[$searchTo] === INF ? -1 : $totalDistancesToV[$searchTo]) . PHP_EOL;
}

djikstra();