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  3. Project Euler #67: Maximum path sum II
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Project Euler #67: Maximum path sum II

  • willianmonts
     + 0 comments

    In PHP

    Since I'll be using a bottom-up approach, I've assembled the triangle in reverse before calling the solution function

    <?php

function solution($triangle) {
    $len = count($triangle);
    foreach ($triangle as $i => &$curr) {
        if ($i == $len - 1) {
            return $curr[0];
        }
        
        $next = &$triangle[$i + 1];
        foreach ($next as $j => $val) {
            $next[$j] += max($curr[$j], $curr[$j + 1]);
        }
    }
}

$_fp = fopen("php://stdin", "r");
$q = intval(trim(fgets($_fp)));

while ($q--) {
    $j = intval(trim(fgets($_fp)));
    $triangle = array_fill(0, $j, null);
    while ($j--) {
        $triangle[$j] = array_map('intval', explode(' ', trim(fgets($_fp))));
    }
    echo solution($triangle), PHP_EOL;
}

fclose($_fp);