Discussion Detail - XAZXOJ

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P1449 后缀表达式
Steven Wang 状元 LV 9 @ 2024-3-14 21:08:05

#include<bits/stdc++.h>
using namespace std;
const int N = 114514 ;
int z[N] ;
stack<int> sum;
string s;
int p(int i){
	int o=1,cum=0;
	for(;s[i]!='.'&&i!=-1&&s[i]!='+'&&s[i]!='-'&&s[i]!='*'&&s[i]!='/';i--,o*=10){
		cum+=(s[i]-'0')*o;
	}
	return cum;
}
int main()
{
	int a,b;
	getline(cin,s);
	for(int i=0;s[i]!='@';i++){
		if(s[i]>='0'&&s[i]<='9') continue;
		if(s[i]=='.'){ 
			sum.push(p(i-1));
			continue;
		}
		if(s[i]=='+'){
			a = sum.top();
			sum.pop();
			b = sum.top();
			sum.pop();
			sum.push(b+a);
		}
		if(s[i]=='-'){
			a = sum.top();
			sum.pop();
			b = sum.top();
			sum.pop();
			sum.push(b-a);
		}if(s[i]=='*'){
			a = sum.top();
			sum.pop();
			b = sum.top();
			sum.pop();
			sum.push(b*a);
		}if(s[i]=='/'){
			a = sum.top();
			sum.pop();
			b = sum.top();
			sum.pop();
			sum.push(b/a);
		}
	}
	cout << sum.top() ;
	return 0;
}
//怨深，泣动

进击的卡勒 LV 8 @ 2024-3-16 16:55:06

//这个看着好理解
#include <bits/stdc++.h>
using namespace std;

const int N = 114514;
int a[N];
int i;
int now;
int main()
{
	char s;
	while((s = getchar()) != '@')
	{
		if(s >= '0' && s <= '9')
		{
			now = 10 * now; 
			now += s - '0'; 	
		}
		else if(s == '.')
		{
			a[++i] = now;
			now = 0;
	
		}	
		else if(s == '+')
		{
			a[i - 1] = a[i - 1] + a[i];
			a[i] = 0;
			i--; 
		}
			else if(s == '-')
		{
			a[i - 1] = a[i - 1] - a[i];
			a[i] = 0;
			i--; 
		}
			else if(s == '*')
		{
			a[i - 1] = a[i - 1] * a[i];
			a[i] = 0;
			i--; 
		}
			else if(s == '/')
		{
			a[i - 1] = a[i - 1] / a[i];
			a[i] = 0;
			i--; 
		}
		else break;
	}
	cout << a[1];
	return 0;
}

liuhanjin LV 10 @ 2024-3-14 21:52:01

这个好像更简单

#include<bits/stdc++.h>
using namespace std;

stack<long long> stk;

int main()
{
	string a;
	cin >> a;
	long long n = 0;
	for(int i = 0; i < a.size(); i++)
	{
		if(a[i] == '.') continue;
		else if(a[i] == '@')
		{
			cout << stk.top() << endl;
			return 0;
		}
		else if(a[i] >= '0' && a[i] <= '9')
		{
			n += a[i] - '0';
			if(a[i + 1] == '.')
			{
				stk.push(n);
				n = 0;	
			}
			else
			{
				n *= 10;
			}
		}
		else if(a[i] == '+')
		{
			long long temp1 = stk.top();
			stk.pop();
			long long temp2 = stk.top();
			stk.pop();
			stk.push(temp1 + temp2);
		}
		else if(a[i] == '-')
		{
			long long temp1 = stk.top();
			stk.pop();
			long long temp2 = stk.top();
			stk.pop();
			stk.push(temp2 - temp1);
		}
		else if(a[i] == '*')
		{
			long long temp1 = stk.top();
			stk.pop();
			long long temp2 = stk.top();
			stk.pop();
			stk.push(temp1 * temp2);
		}
		else if(a[i] == '/')
		{
			long long temp1 = stk.top();
			stk.pop();
			long long temp2 = stk.top();
			stk.pop();
			stk.push(temp2 / temp1);
		}	
	}	
	
	return 0;
}

晴川promax LV 5 @ 2024-3-14 21:09:27

👎