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Commit 36f19e6

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fishercoder1534fishercoder1534
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refactor 224
1 parent 7cf419e commit 36f19e6

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1 file changed

+92
-89
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  • src/main/java/com/fishercoder/solutions

1 file changed

+92
-89
lines changed

‎src/main/java/com/fishercoder/solutions/_224.java

Lines changed: 92 additions & 89 deletions
Original file line numberDiff line numberDiff line change
@@ -5,11 +5,11 @@
55
import java.util.Stack;
66

77
/**
8+
* 224. Basic Calculator
9+
*
810
* Implement a basic calculator to evaluate a simple expression string.
9-
10-
The expression string may contain open ( and closing parentheses ), the plus + or minus sign -, non-negative integers and empty spaces .
11-
12-
You may assume that the given expression is always valid.
11+
* The expression string may contain open ( and closing parentheses ), the plus + or minus sign -, non-negative integers and empty spaces .
12+
* You may assume that the given expression is always valid.
1313
1414
Some examples:
1515
"1 + 1" = 2
@@ -19,95 +19,98 @@ The expression string may contain open ( and closing parentheses ), the plus + o
1919
*/
2020
public class _224 {
2121

22-
public int calculate(String s) {
23-
if (s == null || s.isEmpty()) {
24-
return 0;
25-
}
22+
public static class Solution1 {
23+
24+
public int calculate(String s) {
25+
if (s == null || s.isEmpty()) {
26+
return 0;
27+
}
2628

27-
s = s.replaceAll("\\s", "");
28-
char[] chars = s.toCharArray();
29-
List<String> filteredStr = new ArrayList();
30-
for (int i = 0; i < chars.length; ) {
31-
StringBuilder sb = new StringBuilder();
32-
while (i < chars.length && Character.isDigit(chars[i])) {
33-
sb.append(chars[i]);
34-
i++;
35-
}
36-
if (i == chars.length) {
37-
if (sb.toString().length() != 0) {
38-
filteredStr.add(sb.toString());
39-
}
40-
} else {
41-
if (sb.toString().length() != 0) {
42-
filteredStr.add(sb.toString());
43-
}
44-
if (chars[i] == '+' || chars[i] == '-' || chars[i] == '(' || chars[i] == ')') {
45-
filteredStr.add(String.valueOf(chars[i]));
46-
}
47-
i++;
48-
}
49-
}
29+
s = s.replaceAll("\\s", "");
30+
char[] chars = s.toCharArray();
31+
List<String> filteredStr = new ArrayList();
32+
for (int i = 0; i < chars.length; ) {
33+
StringBuilder sb = new StringBuilder();
34+
while (i < chars.length && Character.isDigit(chars[i])) {
35+
sb.append(chars[i]);
36+
i++;
37+
}
38+
if (i == chars.length) {
39+
if (sb.toString().length() != 0) {
40+
filteredStr.add(sb.toString());
41+
}
42+
} else {
43+
if (sb.toString().length() != 0) {
44+
filteredStr.add(sb.toString());
45+
}
46+
if (chars[i] == '+' || chars[i] == '-' || chars[i] == '(' || chars[i] == ')') {
47+
filteredStr.add(String.valueOf(chars[i]));
48+
}
49+
i++;
50+
}
51+
}
5052

51-
for (String str : filteredStr) {
52-
System.out.print(str);
53-
}
53+
for (String str : filteredStr) {
54+
System.out.print(str);
55+
}
5456

55-
Stack<String> stack1 = new Stack();
56-
Stack<String> stack2 = new Stack();
57-
for (int i = 0; i < filteredStr.size(); ) {
58-
while (i < filteredStr.size() && !filteredStr.get(i).equals(")")) {
59-
stack1.push(filteredStr.get(i));
60-
i++;
61-
}
62-
if (i != filteredStr.size()) {
63-
while (!stack1.isEmpty() && !stack1.peek().equals("(")) {
64-
stack2.push(stack1.pop());
65-
}
66-
stack1.pop();
67-
int exp = 0;
68-
while (!stack2.isEmpty()) {
69-
if (stack2.size() == 1) {
70-
stack1.push(stack2.pop());
71-
break;
72-
}
73-
int operand1 = Integer.parseInt(stack2.pop());
74-
String operator = stack2.pop();
75-
int operand2 = Integer.parseInt(stack2.pop());
76-
if (operator.equals("+")) {
77-
exp = operand1 + operand2;
78-
} else if (operator.equals("-")) {
79-
exp = operand1 - operand2;
80-
}
81-
stack2.push(String.valueOf(exp));
82-
}
83-
i++;
84-
}
85-
}
57+
Stack<String> stack1 = new Stack();
58+
Stack<String> stack2 = new Stack();
59+
for (int i = 0; i < filteredStr.size(); ) {
60+
while (i < filteredStr.size() && !filteredStr.get(i).equals(")")) {
61+
stack1.push(filteredStr.get(i));
62+
i++;
63+
}
64+
if (i != filteredStr.size()) {
65+
while (!stack1.isEmpty() && !stack1.peek().equals("(")) {
66+
stack2.push(stack1.pop());
67+
}
68+
stack1.pop();
69+
int exp = 0;
70+
while (!stack2.isEmpty()) {
71+
if (stack2.size() == 1) {
72+
stack1.push(stack2.pop());
73+
break;
74+
}
75+
int operand1 = Integer.parseInt(stack2.pop());
76+
String operator = stack2.pop();
77+
int operand2 = Integer.parseInt(stack2.pop());
78+
if (operator.equals("+")) {
79+
exp = operand1 + operand2;
80+
} else if (operator.equals("-")) {
81+
exp = operand1 - operand2;
82+
}
83+
stack2.push(String.valueOf(exp));
84+
}
85+
i++;
86+
}
87+
}
8688

87-
if (stack1.size() == 1) {
88-
return Integer.parseInt(stack1.pop());
89-
}
89+
if (stack1.size() == 1) {
90+
return Integer.parseInt(stack1.pop());
91+
}
9092

91-
while (!stack1.isEmpty()) {
92-
stack2.push(stack1.pop());
93-
}
94-
while (!stack2.isEmpty()) {
95-
if (stack2.size() == 1) {
96-
stack1.push(stack2.pop());
97-
break;
98-
}
99-
int exp = 0;
100-
int operand1 = Integer.parseInt(stack2.pop());
101-
String operator = stack2.pop();
102-
int operand2 = Integer.parseInt(stack2.pop());
103-
if (operator.equals("+")) {
104-
exp = operand1 + operand2;
105-
} else if (operator.equals("-")) {
106-
exp = operand1 - operand2;
107-
}
108-
stack2.push(String.valueOf(exp));
109-
}
110-
return Integer.parseInt(stack1.pop());
111-
}
93+
while (!stack1.isEmpty()) {
94+
stack2.push(stack1.pop());
95+
}
96+
while (!stack2.isEmpty()) {
97+
if (stack2.size() == 1) {
98+
stack1.push(stack2.pop());
99+
break;
100+
}
101+
int exp = 0;
102+
int operand1 = Integer.parseInt(stack2.pop());
103+
String operator = stack2.pop();
104+
int operand2 = Integer.parseInt(stack2.pop());
105+
if (operator.equals("+")) {
106+
exp = operand1 + operand2;
107+
} else if (operator.equals("-")) {
108+
exp = operand1 - operand2;
109+
}
110+
stack2.push(String.valueOf(exp));
111+
}
112+
return Integer.parseInt(stack1.pop());
113+
}
114+
}
112115

113116
}

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