java - Remove brackets from an algebraic string containing + and – operators

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public class _Math2 { /** * Remove brackets from an algebraic string containing + and – operators * * http://www.geeksforgeeks.org/remove-brackets-algebraic-string-containing-operators/ * * @param str */ public static String remove_brackets_from_algebric_equation(String str) { char[] chars = str.replaceAll("\\s+", "").toCharArray(); for (int i = 0; i < chars.length; i++) { if(chars[i] == '(') { findBracket(i,chars); break; } } return new String(chars).replaceAll("\\s+", ""); } private static void findBracket(int open, char[] chars) { for (int i = open + 1; i < chars.length; i++) { if(chars[i] == '(') findBracket(i, chars); else if(chars[i] == ')') { removeBrackets(chars, open, i); for (int j = 0; j < chars.length; j++) { if(chars[j] == '(') { findBracket(j , chars); break; } } } } } private static void removeBrackets(char[] chars, int open, int close) { char operator = '+'; for (int i = open - 1; i >= 0; i--) { if(chars[i] == '+' || chars[i] == '-') { operator = chars[i]; break; } } chars[open] = ' '; chars[close] = ' '; if(operator == '+') return; for (int i = open+1; i < chars.length; i++) { char c = chars[i]; chars[i] = c == '+' ? '-' : c == '-' ? '+' : c; } } }