Cod sursa(job #2867478)

Utilizator QwertyDvorakQwerty Dvorak QwertyDvorak Data 10 martie 2022 13:04:45
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 3.15 kb
#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define mp make_pair
#define dbg(x) cout << #x <<": " << x << "\n";
using ll = long long;

class InP {
	FILE *fin;
	char *buff;
	int sp;

public:
	InP(const char *p) {
		fin = fopen(p, "r");
		buff = new char[4096]();
		sp = 4095;
	}
	~InP() {
		fclose(fin);
	}
	char read_ch() {
		sp++;
		if (sp == 4096) {
			fread(buff, 1, 4096, fin);
			sp = 0;
		}
		return buff[sp];
	}

	InP &operator >>(int &n) {
		char c;
		int sgn = 1;
		while (!isdigit(c = read_ch()) && c != '-');
		if (c == '-') {
			n = 0;
			sgn = -1;
		}
		else n = c - '0';
		while (isdigit(c = read_ch()))
			n = n * 10 + c - '0';
		n = n * sgn;
		return *this;
	}

	InP &operator >>(ll &n) {
		char c;
		int sgn = 1;
		while (!isdigit(c = read_ch()) && c != '-');
		if (c == '-') {
			n = 0;
			sgn = -1;
		}
		else n = c - '0';
		while (isdigit(c = read_ch()))
			n = n * 10LL + c - '0';
		n = n * sgn;
		return *this;
	}

	InP &operator >> (char &n) {
		n = read_ch();
		// while ((n = read_ch()) != '\n' && n != ' ');
		return *this;
	}

};

class OuP {
	FILE *fout;
	char *buff;
	int sp;

public:

	OuP(const char *p) {
		fout = fopen(p, "w");
		buff = new char[50000];
		sp = 0;
	}
	~OuP() {
		fwrite(buff, 1, sp, fout);
		fclose(fout);
	}
	void write_ch(char c) {
		if (sp == 50000) {
			fwrite(buff, 1, sp, fout);
			sp = 0;
		}
		buff[sp++] = c;
	}

	OuP &operator <<(int n) {
		if (n <= 9)
			write_ch(n + '0');
		else {
			*(this) << (n / 10);
			write_ch(n % 10 + '0');
		}
		return *this;
	}

	OuP &operator <<(ll n) {
		if (n <= 9)
			write_ch(n + '0');
		else {
			*(this) << (n / 10);
			write_ch(n % 10 + '0');
		}
		return *this;
	}

	OuP &operator <<(char c) {
		write_ch(c);
		return *this;
	}

	OuP &operator <<(const char *c) {
		while (*c) {
			write_ch(*c);
			c++;
		}
		return *this;
	}

};

// InP fin("sortaret.in");
// OuP fout("sortaret.out");

ifstream fin("evaluare.in");
ofstream fout("evaluare.out");

string s;
stack<int> st;
stack<char> op;

bool isop(char c) {
	return strchr("+-*/", c);
}

int priority(char c) {
	if (c == '+' || c == '-')
		return 1;
	if (c == '*' || c == '/')
		return 2;
	return -1;
}

void calc(char op) {
	int R = st.top(); st.pop();
	int L = st.top(); st.pop();
	if (op ==  '+')
		st.push(L + R);
	if (op ==  '-')
		st.push(L - R);
	if (op ==  '*')
		st.push(L * R);
	if (op ==  '/')
		st.push(L / R);
}


int main() {

	fin >> s;

	for (int i = 0; i < s.size(); ++i) {
		if (s[i] == ' ')
			continue;
		if (s[i] == '(') {
			op.push(s[i]);
		}
		else if (s[i] == ')') {
			while (op.top() != '(')
				calc(op.top()), op.pop();
			op.pop();
		}
		else if (isop(s[i])) {
			while (!op.empty() && priority(op.top()) >= priority(s[i]))
				calc(op.top()), op.pop();
			op.push(s[i]);
		}
		else {
			int ac = 0;
			while (s[i] && isdigit(s[i]))
				ac = ac * 10 + s[i ++ ] - '0';
			st.push(ac);
			--i;
		}
	}

	while (!op.empty())
		calc(op.top()), op.pop();

	fout << st.top() << '\n';

// fin.close();
// fout.close();
	return 0;
}