Create 486.cpp

486.cpp

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+// A recursive program to test whether a given
+// string can be segmented into space separated
+// words in dictionary
+#include <iostream>
+using namespace std;
+
+/* A utility function to check whether a word is
+present in dictionary or not. An array of strings
+is used for dictionary. Using array of strings for
+dictionary is definitely not a good idea. We have
+used for simplicity of the program*/
+int dictionaryContains(string word)
+{
+	string dictionary[] = {"mobile","samsung","sam","sung",
+							"man","mango","icecream","and",
+							"go","i","like","ice","cream"};
+	int size = sizeof(dictionary)/sizeof(dictionary[0]);
+	for (int i = 0; i < size; i++)
+		if (dictionary[i].compare(word) == 0)
+		return true;
+	return false;
+}
+
+// returns true if string can be segmented into space
+// separated words, otherwise returns false
+bool wordBreak(string str)
+{
+	int size = str.size();
+
+	// Base case
+	if (size == 0) return true;
+
+	// Try all prefixes of lengths from 1 to size
+	for (int i=1; i<=size; i++)
+	{
+		// The parameter for dictionaryContains is
+		// str.substr(0, i) which is prefix (of input
+		// string) of length 'i'. We first check whether
+		// current prefix is in dictionary. Then we
+		// recursively check for remaining string
+		// str.substr(i, size-i) which is suffix of
+		// length size-i
+		if (dictionaryContains( str.substr(0, i) ) &&
+			wordBreak( str.substr(i, size-i) ))
+			return true;
+	}
+
+	// If we have tried all prefixes and
+	// none of them worked
+	return false;
+}
+
+// Driver program to test above functions
+int main()
+{
+	wordBreak("ilikesamsung")? cout <<"Yes\n": cout << "No\n";
+	wordBreak("iiiiiiii")? cout <<"Yes\n": cout << "No\n";
+	wordBreak("")? cout <<"Yes\n": cout << "No\n";
+	wordBreak("ilikelikeimangoiii")? cout <<"Yes\n": cout << "No\n";
+	wordBreak("samsungandmango")? cout <<"Yes\n": cout << "No\n";
+	wordBreak("samsungandmangok")? cout <<"Yes\n": cout << "No\n";
+	return 0;
+}