Create infix to prefix expression

Author: fuad7161

Data Structure/infix to prefix expression

@@ -0,0 +1,172 @@
+//Author: Fuadul Hasan([email protected])
+//BSMRSTU,Gopalganj
+//#include<bits/stdc++.h>
+#define _USE_MATH_DEFINES
+#include <set>
+#include <map>
+#include <list>
+#include <queue>
+#include <stack>
+#include <cmath>
+#include <ctime>
+#include <cstdio>
+#include <string>
+#include <vector>
+#include <bitset>
+#include <random>
+#include<iomanip>
+#include <cassert>
+#include <cstring>
+#include <sstream>
+#include <complex>
+#include <numeric>
+#include <iostream>
+#include <algorithm>
+#include <functional>
+#include <unordered_set>
+#include <unordered_map>
+using namespace std;
+
+//debug..........
+#define error(args...) {vector<string>_v=split(#args,',');err(_v.begin(),args);cout<<endl;}
+vector<string> split(const string &s, char c) {vector<string>v; stringstream ss(s); string x;while (getline(ss, x, c))v.emplace_back(x); return move(v);} void err(vector<string>::iterator it) {}
+template<typename T, typename... Args>void err(vector<string>::iterator it, T a, Args...args) {cout << it->substr((*it)[0] == ' ', it->length()) << " = " << a << " "; err(++it, args...);}
+
+//............ignore it..................//
+#define F first
+#define S second
+#define Pi atan(1)*4
+#define mp make_pair
+#define pb  push_back
+const int M	= 1e9 + 7;
+#define ld  long double
+#define ll  long long int
+#define happy cin.tie(0);
+#define point(x) cout<<fixed<<setprecision(x)
+int length(string s){return (int)s.size();}
+#define mem(a)  memset(a , 0 ,sizeof a)
+#define memn(a) memset(a , -1 ,sizeof a)
+#define coding ios::sync_with_stdio(false);
+#define Unique(c) (c).resize(unique(all(c))-(c).begin())
+#define vout(v) for (auto z: v) cout << z << " "; cout << endl;
+
+int length(long long x){int l = 0;for(long long i=x;i;i/=10)l++;return l;}
+int dx[8]= {1,0,-1,0,-1,-1,1,1};
+int dy[8]= {0,1,0,-1,-1,1,-1,1}; 
+
+#define rep(i,b,e)  for(__typeof(e) i = (b) ; i != (e + 1) - 2 * ((b) > (e))  ; i += 1 - 2 * ((b) > (e)))
+
+long long Inv_pow(long long a,long long n){ll res = 1;while(n){if(n&1) res = ((res%M)*(a%M))%M;a = ((a%M)*(a%M))%M;n>>=1;}return res%M;}
+// suffix_prefix....
+std::vector<ll> prefix_sum(std::vector<ll> a){int n = a.size();std::vector<ll> prf(n,0);for(int i=0;i<n;i++){
+if(i == 0){prf[i] = a[i];}else{prf[i] = prf[i-1]+a[i];}}return prf;}
+std::vector<ll> suffix_sum(std::vector<ll> a){int n = a.size();std::vector<ll>suf(n,0);for(int i=n-1;i>=0;i--){
+if(i == n-1){suf[i] = a[i];}else{suf[i] = suf[i+1]+a[i];}}return suf;}
+
+long long Lcm(long long a,long long b){return (((a)*(b)))/__gcd(a,b);}
+
+#define Test cout<<"Case #"<<tc++<<": ";
+int tc = 1;
+
+inline void read(std::vector<int> &v){for(int i=0;i<(int)v.size();i++){cin>>(v[i]);}}
+inline void readl(std::vector<ll> &v){for(int i=0;i<(int)v.size();i++){cin>>(v[i]);}}
+
+template<class T> bool remin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
+template<class T> bool remax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
+
+inline void read(int v[],int n){for(int i=0;i<n;i++){cin>>(v[i]);}}
+inline void readl(ll v[],int n){for(int i=0;i<n;i++){cin>>(v[i]);}}
+
+inline int add(int a, int b, int mod) {a += b ; return a >= mod ? a - mod : a ;}
+inline int sub(int a, int b, int mod) {a -= b ; return a < 0 ? a + mod : a ;}
+inline int mul(int a, int b, int mod) {return (ll)a * b % mod ;}
+
+#define   pr 	pair<int, int> 
+#define   vpr 	vector<pr> 
+#define   vi   	std::vector<int>
+#define   vll  	std::vector<ll>
+#define   all(n) n.begin(),n.end()
+
+
+const int Inf           = (int)2e9 + 5;
+const ll  Lnf           = (ll)2e18 + 5;
+const int N             = 5e5 + 5;
+const int NN            = 1e6 + 5;
+
+int prec(char c){
+	if(c == '^'){
+		return 3;
+	}else if(c == '/' or c == '*'){
+		return 2;
+	}else if(c == '+' or c == '-'){
+		return 1;
+	}else{
+		return -1;
+	}
+}
+
+string infixToPostfix(string s){
+	stack<char> st;
+	string result = "";
+
+	for(int i=0;i<s.size();i++){
+		char c = s[i];
+		if((c >= 'a' and c <= 'z') || (c >= 'A' and c <= 'Z'))
+			result += c;
+		else if(c == '('){
+			st.push('(');
+		}else if(c == ')'){
+			while(st.top() != '('){
+				result += st.top();
+				st.pop();
+			}
+			st.pop();
+		}else{
+			while(!st.empty() and prec(s[i]) <= prec(st.top())){
+				result += st.top();
+				st.pop();
+			}
+			st.push(c);
+		}
+	}
+
+	while(!st.empty()){
+		result += st.top();
+		st.pop();
+	}
+	return result;
+}
+
+int solve() 
+{
+	
+	//Test
+
+	string s;
+	cin>>s;
+
+	string t = infixToPostfix(s);
+
+	cout<<t<<endl;
+
+
+	return 0;
+	//error();
+}
+int main(){
+
+	happy coding
+	int test = 1;
+	cin>>test;
+	while (test--)solve();return 0;
+}
+
+/*
+1. Everything happens for something good.
+2. Don't expect anything from anyone except yourself.
+3. Self discipline is the magic power that makes you unstoppable.
+*/
+
+/* Note:
+-> when you use long long. always keep ll in integer number. like 2LL or (ll)i.
+*/