upgrade to python3;add some validator examples

examples/float_validator.cpp

@@ -0,0 +1,54 @@
+// 浮点数误差比较验证程序
+// 编译: g++ -o float_validator float_validator.cpp
+// 使用: ./float_validator input.txt expected.txt result.txt
+
+#include <iostream>
+#include <fstream>
+#include <cmath>
+#include <iomanip>
+using namespace std;
+
+const double EPS = 1e-9;
+
+int main(int argc, char* argv[]) {
+    if (argc != 4) {
+        cout << "WA" << endl;
+        return 0;
+    }
+    
+    ifstream expected(argv[2]);  // 标准答案
+    ifstream result(argv[3]);    // 用户输出
+    
+    if (!expected.is_open() || !result.is_open()) {
+        cout << "WA" << endl;
+        return 0;
+    }
+    
+    double exp_val, res_val;
+    
+    // 读取期望的浮点数
+    if (!(expected >> exp_val)) {
+        cout << "WA" << endl;
+        return 0;
+    }
+    
+    // 读取用户输出的浮点数
+    if (!(result >> res_val)) {
+        cout << "WA" << endl;
+        return 0;
+    }
+    
+    // 比较数值，允许相对误差和绝对误差
+    double diff = fabs(exp_val - res_val);
+    double rel_error = (fabs(exp_val) > EPS) ? diff / fabs(exp_val) : diff;
+    
+    if (diff <= 1e-6 || rel_error <= 1e-6) {  // 放宽误差范围
+        cout << "AC" << endl;
+    } else {
+        cout << "WA" << endl;
+    }
+    
+    expected.close();
+    result.close();
+    return 0;
+}