| 14 | }; |
| 15 | |
| 16 | public static String reduce(String expression, int start, int end) { |
| 17 | if (start == end) { |
| 18 | if (expression.charAt(start) == '1') { |
| 19 | return "1"; |
| 20 | } else if (expression.charAt(start) == '0') { |
| 21 | return "0"; |
| 22 | } |
| 23 | } |
| 24 | int count = 0; |
| 25 | int i = 0; |
| 26 | String[] reduced = new String[3]; |
| 27 | int index = 0; |
| 28 | int left = start; |
| 29 | int right = start; |
| 30 | for (i = start; i <= end; i++) { |
| 31 | if (expression.charAt(i) == '(') { |
| 32 | if (count == 0) { |
| 33 | left = i + 1; |
| 34 | } |
| 35 | count++; |
| 36 | } else if (expression.charAt(i) == ')') { |
| 37 | count--; |
| 38 | if (count == 0) { |
| 39 | right = i - 1; |
| 40 | } |
| 41 | } |
| 42 | if (count == 0) { |
| 43 | reduced[index] = reduce(expression, left, right); |
| 44 | if (index == 0) { |
| 45 | reduced[index + 1] = Character.toString(expression.charAt(i + 1)); |
| 46 | i += 1; |
| 47 | left = i + 1; |
| 48 | right = i + 1; |
| 49 | } |
| 50 | index += 2; |
| 51 | } |
| 52 | } |
| 53 | if (reduced[1].equals("&")) { |
| 54 | if (reduced[0].equals("1") && reduced[2].equals("1")) { |
| 55 | return "1"; |
| 56 | } |
| 57 | return "0"; |
| 58 | } else if (reduced[1].equals("|")) { |
| 59 | if (reduced[0].equals("1") || reduced[2].equals("1")) { |
| 60 | return "1"; |
| 61 | } |
| 62 | return "0"; |
| 63 | } else if (reduced[1].equals("^")) { |
| 64 | if (reduced[0].equals("1") && reduced[2].equals("0")) { |
| 65 | return "1"; |
| 66 | } else if (reduced[0].equals("0") && reduced[2].equals("1")) { |
| 67 | return "1"; |
| 68 | } |
| 69 | return "0"; |
| 70 | } |
| 71 | return "0"; |
| 72 | } |
| 73 | |