simple_wildcard_match.cpp

puzzles/interviews/training/simple_wildcard_match.cpp

@@ -0,0 +1,94 @@
+/*
+VIM: let b:lcppflags="-std=c++14 -O2 -pthread -I."
+VIM: let b:wcppflags="/O2 /EHsc /DWIN32"
+VIM-: let b:cppflags=g:Iboost.g:Itbb
+VIM-: let b:ldflags=g:Lboost.g:Ltbb
+VIM-: let b:ldlibpath=g:Bboost.g:Btbb
+VIM-: let b:argv=""
+*/
+#include <iostream>
+#include <exception>
+#include <chrono>
+#include <string>
+
+/*
+Simple wildcard match.
+
+*/
+
+bool wildcard_match(const std::string& input, const std::string& pattern)
+{
+    int j = 0;
+    int i = 0;
+    int restart_idx = -1;
+    while ( i < input.size() )
+    {
+        while ( j < pattern.size() && pattern[j] == '*' ){
+            restart_idx = ++j;
+        }
+        if ( j<pattern.size() && pattern[j] == input[i] ) {
+            ++i;
+            ++j;
+        }
+        else if ( j>= 0 && pattern[j-1] == '*' ) {
+            ++i;
+        }
+        else if ( restart_idx > 0 ) {
+            i -= j - restart_idx -1;
+            j = restart_idx;
+        }
+        else {
+            return false;
+        }
+    }
+    while ( j < pattern.size() && pattern[j] == '*' ){
+        ++j;
+    }
+    return j == pattern.size();
+}
+
+void test(const std::string& input, const std::string& pattern)
+{
+    std::cout << input << " x " << pattern 
+            << " == " << wildcard_match(input,pattern)
+            << std::endl;
+}
+
+
+int main ( void )
+{try{
+    auto begin = std::chrono::high_resolution_clock::now();
+
+    test("zebra", "dog");
+    test("zebra", "zebra");
+    test("zebra", "*br*");
+    test("zebra", "*bi*");
+    test("zebra", "*br*a");
+    test("zebra", "*br*b");
+    test("zebra", "z**a");
+    test("zebra", "z*a");
+    test("zebra", "x**a");
+    test("zebrabrb", "*brb*");
+    test("zebra", "*bra*");
+    test("zebrazebrazebra", "*bra*zeb*zeb*");
+    test("zebrbzebrazebra", "*bra*zeb*zeb*");
+    test("zebrbzebrazebra", "*bra*zeb*");
+
+    auto end = std::chrono::high_resolution_clock::now();
+    std::chrono::duration<double> seconds = end - begin;
+    std::cout << "Time: " << seconds.count() << std::endl;
+    return 0;
+}
+catch ( const std::exception& e )
+{
+    std::cerr << std::endl
+            << "std::exception(\"" << e.what() << "\")." << std::endl;
+    return 2;
+}
+catch ( ... )
+{
+    std::cerr  << std::endl
+            << "unknown exception." << std::endl;
+    return 1;
+}}
+