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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4.  
  5. class ExpressionParser {
  6. 	private static String operators = "+-*/";
  7. 	private static String delimiters = "() " + operators;
  8.  
  9. 	private static boolean isDelimiter(String token) {
  10. 		if (token.length() != 1) return false;
  11. 		for (int i = 0; i < delimiters.length(); i++) {
  12. 			if (token.charAt(0) == delimiters.charAt(i)) return true;
  13. 		}
  14. 		return false;
  15. 	}
  16.  
  17. 	private static boolean isFunction(String token) {
  18. 		if (token.equals("sqrt") || token.equals("cube") || token.equals("pow10")) return true;
  19. 		return false;
  20. 	}
  21.  
  22. 	private static int priority(String token) {
  23. 		if (token.equals("(")) return 1;
  24. 		if (token.equals("+") || token.equals("-")) return 2;
  25. 		if (token.equals("*") || token.equals("/")) return 3;
  26. 		return 4;
  27. 	}
  28.  
  29. 	public static List<String> parse(String infix) {
  30. 		List<String> postfix = new ArrayList<String>();
  31. 		Deque<String> stack = new ArrayDeque<String>();
  32. 		StringTokenizer tokenizer = new StringTokenizer(infix, delimiters, true);
  33. 		String prev = "";
  34. 		String curr = "";
  35. 		while (tokenizer.hasMoreTokens()) {
  36. 			curr = tokenizer.nextToken();
  37. 			if (curr.equals(" ")) continue;
  38. 			if (isFunction(curr)) stack.push(curr);
  39. 			else if (isDelimiter(curr)) {
  40. 				if (curr.equals("(")) stack.push(curr);
  41. 				else if (curr.equals(")")) {
  42. 					while (!stack.peek().equals("(")) {
  43. 						postfix.add(stack.pop());
  44. 					}
  45. 					stack.pop();
  46. 					if (!stack.isEmpty() && isFunction(stack.peek())) {
  47. 						postfix.add(stack.pop());
  48. 					}
  49. 				}
  50. 				else {
  51. 					if (curr.equals("-") && (prev.equals("") || (isDelimiter(prev)  && !prev.equals(")")))) {
  52. 						// унарный минус
  53. 						curr = "u-";
  54. 					}
  55. 					else {
  56. 						while (!stack.isEmpty() && (priority(curr) <= priority(stack.peek()))) {
  57. 							postfix.add(stack.pop());
  58. 						}
  59.  
  60. 					}
  61. 					stack.push(curr);
  62. 				}
  63.  
  64. 			}
  65.  
  66. 			else {
  67. 				postfix.add(curr);
  68. 			}
  69. 			prev = curr;
  70. 		}
  71.  
  72. 		while (!stack.isEmpty()) {
  73. 			postfix.add(stack.pop());
  74. 		}
  75. 		return postfix;
  76. 	}
  77. }
  78.  
  79. class Ideone {
  80. 	public static Double calc(List<String> postfix) {
  81. 		Deque<Double> stack = new ArrayDeque<Double>();
  82. 		for (String x : postfix) {
  83. 			if (x.equals("sqrt")) stack.push(Math.sqrt(stack.pop()));
  84. 			else if (x.equals("cube")) {
  85. 				Double tmp = stack.pop();
  86. 				stack.push(tmp * tmp * tmp);
  87. 			}
  88. 			else if (x.equals("pow10")) stack.push(Math.pow(10, stack.pop()));
  89. 			else if (x.equals("+")) stack.push(stack.pop() + stack.pop());
  90. 			else if (x.equals("-")) {
  91. 				Double b = stack.pop(), a = stack.pop();
  92. 				stack.push(a - b);
  93. 			}
  94. 			else if (x.equals("*")) stack.push(stack.pop() * stack.pop());
  95. 			else if (x.equals("/")) {
  96. 				Double b = stack.pop(), a = stack.pop();
  97. 				stack.push((double) Math.round(a / b));
  98. 			}
  99. 			else if (x.equals("u-")) stack.push(-stack.pop());
  100. 			else stack.push(Double.valueOf(x));
  101. 		}
  102. 		return stack.pop();
  103. 	}
  104.  
  105. 	public static void main (String[] args) {
  106. 		Scanner in = new Scanner(System.in);
  107. 		String s = in.nextLine();
  108. 		ExpressionParser n = new ExpressionParser();
  109. 		List<String> expression = n.parse(s);
  110. 		for (String x : expression) System.out.print(x + " ");
  111. 		System.out.println();
  112. 		System.out.println(calc(expression));
  113. 	}
  114. }
Runtime error #stdin #stdout #stderr 0.16s 321344KB
comments (?)
stdin
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pow10(2)-95+4*8-
stdout
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2 pow10 95 - 4 8 * + -
stderr
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Exception in thread "main" java.util.NoSuchElementException
	at java.util.ArrayDeque.removeFirst(ArrayDeque.java:280)
	at java.util.ArrayDeque.pop(ArrayDeque.java:517)
	at Ideone.calc(Main.java:91)
	at Ideone.main(Main.java:112)
https://ideone.com/y7Gxr1
obrat polsk zap
language:
Java (12.0.1)
created:
8 years ago
visibility:
secret

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