阿里编程逆波兰表达式有人ac吗
只有40%哪里有问题啊
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.Stack;
public class Main {
public static void main(String[] args) {
ArrayList<Integer> inputs = new ArrayList<Integer>();
Scanner in = new Scanner(System.in);
String line = in.nextLine();
if(line != null && !line.isEmpty()) {
int res = resolve(line.trim());
System.out.println(String.valueOf(res));
}
}
// write your code here
public static int resolve(String expr) {
StringBuffer sb = new StringBuffer();
for(int i=0;i<expr.length();i++){
if(expr.charAt(i)==' '){
continue;
}else{
sb.append(expr.charAt(i));
//sb.append(" ");
}
}
String test = sb.toString();
//String[] sp=test.split(" ");
char[] chas = test.toCharArray();
Stack<Integer> stack = new Stack<Integer>();
for(int i=0;i<chas.length;i++){
if(chas[i]=='*'){
if(stack.size()<2){
return -1;
}
int m1=stack.pop();
int m2=stack.pop();
int m = m1*m2;
stack.push(m);
}else if(chas[i]=='+'){
if(stack.size()<2){
return -1;
}
int m1=stack.pop();
int m2=stack.pop();
int m = m1+m2;
stack.push(m);
}else if(chas[i]=='^'){
int x = stack.pop();
x=x+1;
stack.push(x);
}else{
String cs = chas[i]+"";
int value = Integer.valueOf(cs);
if(stack.size()==16){
return -2;
}
stack.push(value);
}
}
return stack.peek();
}
}
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