Hm3

Exercise/Homework3/Q1过了的版本.cpp

@@ -0,0 +1,194 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+//<2F><><EFBFBD><EFBFBD>
+long long fastpow(long long d, long long u){
+	//d^u<><75><EFBFBD>ÿ<EFBFBD><C3BF><EFBFBD><EFBFBD><EFBFBD> 
+	long long result = 1, base = d, b = u;
+	while(b > 0){
+		if(b & 1) result *= base; 
+		base *= base;
+		b >>= 1;
+	} 
+	return result; 
+}
+
+int level(char c){
+	switch(c){
+		case '+':
+		case '-': {
+			return 1; 
+			break;
+		} 
+		case '*':
+		case '/': {
+			return 2;
+			break;
+		}
+		case '^': {
+			return 3;
+			break;
+		}
+		default: {
+			return 0;
+			break;
+		}
+	}
+}
+
+int findexp(const string& s, int l, int r) {
+    int pos = -1;
+    int min_level = 114514;
+    int js = 0;
+    for (int i = r; i >= l; i--) {
+        if (s[i] == ')') js--; 
+        else if (s[i] == '(') js++;
+        
+        if (js == 0 && level(s[i])) {
+            int lev = level(s[i]);
+            if (lev < min_level || (lev == min_level && s[i] == '^')) {
+                min_level = lev;
+                pos = i;
+            }
+        }
+    }
+    return pos;	
+}
+
+long long toNum(const string& s, int l, int r) {
+    long long tmp = 0;
+    
+    // <20><><EFBFBD><EFBFBD><EFBFBD>ո<EFBFBD>
+    while (l <= r && s[l] == ' ') l++;
+    while (l <= r && s[r] == ' ') r--;
+    
+    if (l > r) return 0;
+    
+    // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҵ<EFBFBD><D2B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
+    for (int i = l; i <= r; i++) {
+        if (isdigit(s[i])) {
+            tmp = tmp * 10 + (s[i] - '0');
+        } else {
+            return 0; // <20>Ƿ<EFBFBD><C7B7>ַ<EFBFBD>
+        }
+    }
+    
+    return tmp; 
+}
+
+struct Node{
+	char sign;
+	long long num;
+	Node* left;
+	Node* right;
+	
+	Node(): sign('?'), num(-1), left(nullptr), right(nullptr) {}
+	Node(char s): sign(s), num(-1), left(nullptr), right(nullptr) {}
+	Node(long long n): sign('?'), num(n), left(nullptr), right(nullptr) {}
+};
+
+class Expression{
+public:
+	string exp;
+	Node* root;
+	long long result;
+	bool isValid; 
+	
+	Expression(const string& s): exp(s), root(nullptr), result(-1), isValid(true) {}
+	
+	void inorder(Node* r){
+		if(!r) return;
+		inorder(r->left);
+        if (r->sign == '?') cout << r->num;
+        else cout << r->sign;
+		inorder(r->right);
+	}
+	
+	Node* build(const string& s, int l, int r){
+		//[l, r]
+		//<2F><><EFBFBD><EFBFBD><EFBFBD>ո<EFBFBD> 
+		while(l <= r && s[l] == ' ') l++;
+		while(l <= r && s[r] == ' ') r--;
+		if(l > r) return nullptr;
+		//<2F><><EFBFBD><EFBFBD><EFBFBD>ⲿ<EFBFBD><E2B2BF><EFBFBD><EFBFBD> 
+		if(s[l] == '(' && s[r] == ')'){
+			bool hasQuote = true; 
+			int js = 0;
+			for(int i = l; i <= r; i++){
+				if(s[i] == '(') js++;
+				else if(s[i] == ')') js--;
+				
+				if(js == 0 && i != r){
+					hasQuote = false;
+					break;	
+				}
+			}
+			if (hasQuote) return build(s, l + 1, r - 1);
+		}
+		
+		int pos = findexp(s, l, r);
+		//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
+		if(pos == -1) {
+			long long x = toNum(s, l, r);
+			return new Node(x);
+		}
+		Node* tmp = new Node(s[pos]);
+		tmp->left = build(s, l, pos - 1);
+		tmp->right = build(s, pos + 1, r); 
+		return tmp;
+	}
+	
+	long long calc(Node* r, bool& isValid){
+		if(!r) return 0; 
+		//<2F><><EFBFBD><EFBFBD>
+		if(r->sign == '?') return r->num;
+		
+		//<2F><><EFBFBD><EFBFBD>
+		long long left = calc(r->left, isValid);
+		long long right = calc(r->right, isValid); 
+		if(r->num == -1){
+			char c = r->sign;
+			switch(c){
+				case '+': return left + right;
+				case '-': return left - right;
+				case '*': return left * right;
+				case '/': {
+					if(right == 0) {
+						isValid = false;
+						return 0;
+					}
+					else return left / right;
+				} 
+				case '^': {
+    				return fastpow(left, right);
+				}
+				default: return 0;
+			}
+		}
+		return 0;
+	}
+	void print(){
+		inorder(root);
+	}
+}; 
+
+int main(){
+	string s;
+	while(getline(cin, s)){
+    	if (s.empty()) {
+        	cout << "INVALID" << endl;
+        	continue;
+    	}
+    	Expression tree(s);
+    	tree.root = tree.build(s, 0, s.length()-1);
+    	if (!tree.root) {
+        	cout << "INVALID" << endl;
+        	continue;
+    	}
+    	long long result = tree.calc(tree.root, tree.isValid);
+    	if(tree.isValid) cout << result << endl;
+    	else cout << "INVALID" << endl;
+	}
+	return 0;
+}