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  1. <?php
  2.  
  3. function isPossible($toCheck){
  4. 	$toCheck=substr($toCheck, 1, -1);
  5. 	$pars = 0;
  6. 	for($i=0; $i<strlen($toCheck); $i++){
  7. 		if($toCheck[$i]=="(") $pars++;
  8. 		if($toCheck[$i]==")") $pars--;
  9. 		if($pars<0) return false;
  10. 	}
  11. 	return true;
  12. }
  13.  
  14. function trimpars($toTrim){
  15. 	$len = strlen($toTrim);
  16. 	if($toTrim[0]=="(" && $toTrim[$len-1]==")"){
  17. 		if(isPossible($toTrim)) $toTrim = substr($toTrim, 1, -1);
  18. 	}
  19. 	return $toTrim;
  20. }
  21.  
  22. class TreeCalc {
  23. 	public $left;
  24. 	public $right;
  25. 	private $value;
  26. 	private $leaf;
  27.  
  28. 	public function __construct(){
  29. 		$this->left = null;
  30. 		$this->right = null;
  31. 		$this->value = null;
  32. 		$this->leaf = false;				
  33. 	}
  34.  
  35. 	public function isLeaf(){
  36. 		return $this->leaf;
  37. 	}
  38.  
  39. 	public function getValue(){
  40. 		return $this->value;
  41. 	}
  42.  
  43. 	private function tokenize($inputString){
  44. 		$pars = 0;
  45. 		$weight = -1;				
  46. 		$tok = -1;
  47. 		$op = "";
  48. 		for($i=0; $i<strlen($inputString); $i++){
  49. 			switch($inputString[$i]){
  50. 				case "(" : 
  51. 					$pars++;
  52. 					break;
  53. 				case ")" : 
  54. 					$pars--;
  55. 					break;
  56. 				case "+": 
  57. 					if($pars>0) break;
  58. 					if($weight < 10){
  59. 						$tok = $i;
  60. 						$op = "+";
  61. 						$weight = 10;
  62. 					}
  63. 					break;
  64. 				case "-":
  65. 					if($pars>0) break;
  66. 					if($weight < 10){
  67. 						$tok = $i;
  68. 						$op = "-";
  69. 						$weight = 10;
  70. 					}
  71. 					break;
  72. 				case "*":
  73. 					if($pars>0) break;
  74. 					if($weight < 5){
  75. 						$tok = $i;
  76. 						$op = "*";
  77. 						$weight = 5;
  78. 					}
  79. 					break;
  80. 				case "/":
  81. 					if($pars>0) break;
  82. 					if($weight < 5){
  83. 						$tok = $i;
  84. 						$op = "/";
  85. 						$weight = 5;
  86. 					}
  87. 					break;
  88. 				case "^":
  89. 					if($pars>0) break;
  90. 					if($weight < 1){
  91. 						$tok = $i;
  92. 						$op = "^";
  93. 						$weight = 1;
  94. 					}
  95. 					break;
  96. 			}
  97. 		}
  98. 		if($weight==-1){
  99. 			$this->leaf = true;
  100. 			$this->value = $inputString;
  101. 			return;
  102. 		}
  103. 		$this->value=$op;
  104. 		$leftString = substr($inputString, 0, $tok);
  105. 		$leftString = trim($leftString);
  106. 		$leftString = trimpars($leftString);
  107.  
  108. 		$rightString = substr($inputString, $tok+1);
  109. 		$rightString = trim($rightString);
  110. 		$rightString = trimpars($rightString);
  111.  
  112. 		$this->left = new TreeCalc();
  113. 		$this->left->tokenize($leftString);
  114. 		$this->right = new TreeCalc();
  115. 		$this->right->tokenize($rightString);
  116. 	}
  117.  
  118. 	public function debugPrint(){
  119. 		echo $this->value;
  120. 		if($this->left != null) $this->left->debugPrint();
  121. 		if($this->right != null) $this->right->debugPrint();
  122. 	}
  123.  
  124. 	private function compute(){
  125. 		if($this->isLeaf()) return;
  126. 		if($this->left->isLeaf()==false){
  127. 			$this->left->compute();
  128. 		}
  129. 		if($this->right->isLeaf()==false){
  130. 			$this->right->compute();
  131. 		}
  132. 		switch($this->value){
  133. 			case "+":
  134. 				$this->value = $this->left->getValue() + $this->right->getvalue();
  135. 				break;
  136. 			case "-":
  137. 				$this->value = $this->left->getValue() - $this->right->getValue();
  138. 				break;
  139. 			case "*":
  140. 				$this->value = $this->left->getValue() * $this->right->getValue();
  141. 				break;
  142. 			case "/":
  143. 				$this->value = $this->left->getValue() / $this->right->getValue();
  144. 				break;
  145. 			case "^":
  146. 				$this->value = pow($this->left->getValue(), $this->right->getValue());
  147. 				break;
  148. 		}
  149. 		$this->leaf = true;
  150. 		$this->left = null;
  151. 		$this->right = null;
  152. 	}
  153.  
  154. 	public function calculate($toCalc){
  155. 		$this->tokenize($toCalc);
  156. 		$this->compute();
  157. 		return $this->getValue();
  158. 	}
  159. }
  160.  
  161.  
  162. $test = new TreeCalc();
  163. echo $test->calculate("3*2^(2+3)+((2+2)*2)-1");
Success #stdin #stdout 0s 82880KB
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https://ideone.com/yEFzJi
language:
PHP (php 7.3.5)
created:
6 years ago
visibility:
public

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