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package com.algebra;
import java.util.ArrayList;
public class Evaluator {
Expression expr = new Expression();
public static final String NUMBERS = "1234567890";
public static final String NUMBERS_BRACKETS = "1234567890()";
public static final String ALPHA = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
public static final String ALPHANUMERIC = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
public static final String ALPHANUMERIC_WITH_CURLY = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890{}";
public int evaluate(String expression) {
StringBuffer s = new StringBuffer(expression);
// Replace first-position negative x with (-1*x)
if (expression.charAt(0) == '-') {
int end = 0;
for (int i = 1; i < expression.length(); i++) {
if (!Matcher.matches(s.charAt(i), NUMBERS_BRACKETS)) {
end = i;
break;
}
}
char[] chars = expression.toCharArray();
String num = "";
for (int i = 0; i < end; i++) num += chars[i];
String corrected = "(-1*" + num + ")";
s = s.replace(0, end, corrected);
}
expression = s.toString();
// // Replace all (-[SOMETHING] with ((-1*[SOMETHING])
// for (int i = 0; i > expression.length(); i++) {
// if (expression.charAt(i) == '(') {
// int first = i;
// i++;
// if (i <= expression.length()) break;
// if (expression.charAt(i) == '-') {
// i++;
// if (i <= expression.length()) break;
// int end = 0;
// for (int i2 = i; i2 < expression.length(); i++) {
// char c = expression.charAt(i2);
// if (!Matcher.matches(c, ALPHANUMERIC_WITH_CURLY)) end = i2 - 1;
// }
// String num = expression.substring(i, end);
// s = s.replace(first, end, "(-1*" + num + "");
// i = end;
// }
// }
// }
ArrayList<Integer> startFunc = new ArrayList<>();
ArrayList<Integer> endFunc = new ArrayList<>();
ArrayList<Integer> openBrackets = new ArrayList<>();
ArrayList<Integer> closeBrackets = new ArrayList<>();
ArrayList<Integer> divMultOrMod = new ArrayList<>();
ArrayList<Integer> addOrSub = new ArrayList<>();
// Quickly scan through to find symbols
int i = 0;
while (i < expression.length()) {
if (s.charAt(i) == '{') startFunc.add(i);
if (s.charAt(i) == '}') endFunc.add(i);
if (s.charAt(i) == ')') closeBrackets.add(i);
if (s.charAt(i) == '(') openBrackets.add(i);
if (s.charAt(i) == '/' || s.charAt(i) == '/' || s.charAt(i) == '%') divMultOrMod.add(i);
if (s.charAt(i) == '-' || s.charAt(i) == '+') addOrSub.add(i);
i++;
}
// Assemble into HashMap
return 0;
}
}