<?php
/*
* Gnieark's anwser to euler problem 18
* https://projecteuler.net/problem=18
*/

$triangleStr="75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23";

$arr=explode("\n",$triangleStr);
$triangle=array();
foreach($arr as $line){
    $triangle[]=explode(" ",$line);
}

//se placer sur l'avant derniere ligne.
while(count($triangle)>1){
    $i=count($triangle) -2;
    for($cell=0; $cell < count($triangle[$i]); $cell++){
        if($triangle[$i +1 ][$cell] > $triangle[$i +1 ][$cell + 1]){
            $triangle[$i][$cell] = $triangle[$i][$cell] + $triangle[$i +1 ][$cell];
        }else{
            $triangle[$i][$cell] = $triangle[$i][$cell] + $triangle[$i +1 ][$cell +1];
        }
    }
    //remove last line
    unset($triangle[$i+1]);
}
echo $triangle[0][0];