Hm3
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e2hang
214
Exercise/Homework3/Q1.cpp
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214
Exercise/Homework3/Q1.cpp
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#include <iostream>
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#include <string>
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using namespace std;
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//<2F>뷨<EFBFBD><EBB7A8><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʽ<EFBFBD><CABD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>м<EFBFBD><D0BC>㣨<EFBFBD><E3A3A8><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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//<2F><>ȻҲ<C8BB><D2B2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ջ<EFBFBD><D5BB>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֣<EFBFBD><D6A3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ң<EFBFBD>
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//<2F><><EFBFBD><EFBFBD>
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long long fastpow(long long d, long long u){
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//d^u<><75><EFBFBD>ÿ<EFBFBD><C3BF><EFBFBD><EFBFBD><EFBFBD>
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long long result = 1, base = d, b = u;
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while(b > 0){
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if(b & 1) result *= base;
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base *= base;
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b >>= 1;
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}
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return result;
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}
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int level(char c){
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switch(c){
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case '+':
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case '-': {
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return 1;
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break;
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}
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case '*':
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case '/': {
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return 2;
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break;
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}
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case '^': {
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return 3;
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break;
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}
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default: {
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return 0;
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break;
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}
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}
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}
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int findexp(const string& s, int l, int r) {
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int pos = -1;
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int min_level = 114514;
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int js = 0;
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for (int i = r; i >= l; i--) {
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if (s[i] == ')') js--;
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else if (s[i] == '(') js++;
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if (js == 0 && level(s[i])) {
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// <20><><EFBFBD><EFBFBD><EFBFBD>ҽ<EFBFBD><D2BD>ϵ<EFBFBD>^<5E><>ʹ<EFBFBD><CAB9><<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><=
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if ((s[i] == '^' && level(s[i]) < min_level) ||
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(s[i] != '^' && level(s[i]) <= min_level)) {
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min_level = level(s[i]);
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pos = i;
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}
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}
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}
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return pos;
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}
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long long toNum(const string& s, int l, int r) {
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long long tmp = 0;
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// <20><><EFBFBD><EFBFBD><EFBFBD>ո<EFBFBD>
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while (l <= r && s[l] == ' ') l++;
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while (l <= r && s[r] == ' ') r--;
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if (l > r) return 0;
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// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҵ<EFBFBD><D2B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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for (int i = l; i <= r; i++) {
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if (isdigit(s[i])) {
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tmp = tmp * 10 + (s[i] - '0');
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} else {
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return 0; // <20>Ƿ<EFBFBD><C7B7>ַ<EFBFBD>
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}
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}
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return tmp;
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}
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/*
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ŵİ汾
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long long toNum(const string& s, int l, int r){
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long long tmp = 0;
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bool neg = false;
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if (s[l] == '-') { neg = true; l++; }
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for(int i = l; i <= r; i++){
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if(isdigit(s[i])) tmp = tmp * 10 + (s[i] - '0');
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}
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return neg ? -tmp : tmp;
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}
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*/
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struct Node{
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char sign;
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long long num;
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Node* left;
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Node* right;
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Node(): sign('?'), num(-1), left(nullptr), right(nullptr) {}
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Node(char s): sign(s), num(-1), left(nullptr), right(nullptr) {}
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Node(long long n): sign('?'), num(n), left(nullptr), right(nullptr) {}
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};
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class Expression{
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public:
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string exp;
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Node* root;
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long long result;
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bool isValid;
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Expression(const string& s): exp(s), root(nullptr), result(-1), isValid(true) {}
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void inorder(Node* r){
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if(!r) return;
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inorder(r->left);
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if (r->sign == '?') cout << r->num;
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else cout << r->sign;
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inorder(r->right);
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}
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Node* build(const string& s, int l, int r){
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//[l, r]
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//<2F><><EFBFBD><EFBFBD><EFBFBD>ո<EFBFBD>
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while(l <= r && s[l] == ' ') l++;
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while(l <= r && s[r] == ' ') r--;
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if(l > r) return nullptr;
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//<2F><><EFBFBD><EFBFBD><EFBFBD>ⲿ<EFBFBD><E2B2BF><EFBFBD><EFBFBD>
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if(s[l] == '(' && s[r] == ')'){
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bool hasQuote = true;
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int js = 0;
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for(int i = l; i <= r; i++){
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if(s[i] == '(') js++;
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else if(s[i] == ')') js--;
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if(js == 0 && i != r){
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hasQuote = false;
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break;
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}
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}
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if (hasQuote) return build(s, l + 1, r - 1);
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}
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int pos = findexp(s, l, r);
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//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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if(pos == -1) {
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long long x = toNum(s, l, r);
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//cout << "*" << r << endl; <20><>Ϊʲô<CAB2><C3B4><EFBFBD><EFBFBD>0
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return new Node(x);
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//<2F><><EFBFBD>·<EFBFBD><C2B7>ڵ<EFBFBD>
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}
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Node* tmp = new Node(s[pos]);
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tmp->left = build(s, l, pos - 1);
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tmp->right = build(s, pos + 1, r);
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return tmp;
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}
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long long calc(Node* r, bool& isValid){
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if(!r) return 0;
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//<2F><><EFBFBD><EFBFBD>
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if(r->sign == '?') return r->num;
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//<2F><><EFBFBD><EFBFBD>
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long long left = calc(r->left, isValid);
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long long right = calc(r->right, isValid);
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if(r->num == -1){
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char c = r->sign;
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switch(c){
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case '+': return left + right;
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case '-': return left - right;
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case '*': return left * right;
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case '/': {
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if(right == 0) {
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isValid = false;
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return 0;
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}
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else return left / right;
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}
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case '^': {
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if(left == 0 && right == 0) { isValid = false; return 0; }
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return fastpow(left, right);
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break;
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}
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default: return 0;
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}
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}
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}
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void print(){
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inorder(root);
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}
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};
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int main(){
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/*
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string s;
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getline(cin, s);
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Expression tree(s);
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tree.root = tree.build(s, 0, s.length() - 1);
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//tree.print();
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cout << tree.calc(tree.root, tree.isValid) << endl;
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//if(!tree.isValid && result != -1) cout << result <<endl;
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//else cout << "Invalid" << endl; */
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string s;
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while(getline(cin, s)){
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Expression tree(s);
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tree.root = tree.build(s, 0, s.length()-1);
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long long result = tree.calc(tree.root, tree.isValid);
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if(tree.isValid) cout << result << endl;
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else cout << "INVALID" << endl;
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}
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return 0;
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}
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