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| 1 | +class Solution { |
| 2 | + |
| 3 | + /** |
| 4 | + * @param String $s |
| 5 | + * @return Boolean |
| 6 | + */ |
| 7 | + function isNumber($s) { |
| 8 | + $isE = false; |
| 9 | + $isPoint = false; |
| 10 | + $lastChar = -1; |
| 11 | + $llastChar = -1; |
| 12 | + if(strlen($s)==1 && !(ord($s[0])>=48 && ord($s[0])<=57)){ |
| 13 | + return false; |
| 14 | + } |
| 15 | + $s=trim($s); |
| 16 | + for($i=0;$i<strlen($s);$i++){ |
| 17 | + $t = ord($s[$i]); |
| 18 | + if($i==0 && $t==101){ |
| 19 | + return false; |
| 20 | + } |
| 21 | + if(!(($t>=48 && $t<=57) || $t==101 || $t== 43 || $t==45 || $t==46)){ |
| 22 | + return false; |
| 23 | + } |
| 24 | + if($t == 101){ |
| 25 | + if($isE){ |
| 26 | + return false; |
| 27 | + } |
| 28 | + if($i == strlen($s)-1){ |
| 29 | + return false; |
| 30 | + } |
| 31 | + if($lastChar==43 || $lastChar==45 || $lastChar==46){ |
| 32 | + if($llastChar == -1){ |
| 33 | + return false; |
| 34 | + } |
| 35 | + } |
| 36 | + $isE = true; |
| 37 | + } |
| 38 | + if($t == 46 ){ |
| 39 | + if($isE){ |
| 40 | + return false; |
| 41 | + } |
| 42 | + if($i == strlen($s)-1 && !($lastChar>=48 && $lastChar<=57)){ |
| 43 | + return false; |
| 44 | + } |
| 45 | + if($isPoint){ |
| 46 | + return false; |
| 47 | + } |
| 48 | + $isPoint = true; |
| 49 | + } |
| 50 | + if(($t==43 || $t==45)&& $i!=0 && ($lastChar!=101 ||($lastChar==101 && $i == strlen($s)-1))){ |
| 51 | + return false; |
| 52 | + } |
| 53 | + $llastChar = $lastChar; |
| 54 | + $lastChar = $t; |
| 55 | + } |
| 56 | + return true; |
| 57 | + } |
| 58 | +} |
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