From 02d7fa727a5f0bf87523090376677c55e4707e12 Mon Sep 17 00:00:00 2001
From: AnupamaTK <43145867+AnupamaTK@users.noreply.github.com>
Date: Wed, 12 May 2021 14:41:52 +0530
Subject: [PATCH] Create Blocksort.cpp

---
 Cpp/Blocksort.cpp | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 Cpp/Blocksort.cpp

diff --git a/Cpp/Blocksort.cpp b/Cpp/Blocksort.cpp
new file mode 100644
index 0000000..75bb4a4
--- /dev/null
+++ b/Cpp/Blocksort.cpp
@@ -0,0 +1,48 @@
+#include <vector>
+#include <iostream>
+#include <algorithm>
+
+class Blocksort
+{
+public:
+	static std::string encode(const std::string &input,int &top);
+	static std::string decode(const std::string &input,int top);
+};
+
+
+std::string Blocksort::encode(const std::string &input, int &top)
+{
+	std::string buff,result;
+	buff = input + input;
+	std::vector<std::string> vectemp;
+  
+	for(int i=0; i < buff.size()/2;++i){
+		std::string temp=buff.substr(i,input.size());	
+		vectemp.push_back(temp);
+	}
+
+	std::stable_sort(vectemp.begin(),vectemp.end());
+
+	for(int i=0; i < vectemp.size();++i){
+		if( input == vectemp[i] ) top = i;
+		result += *(vectemp[i].end()-1);
+	}
+	return result;
+}
+
+std::string Blocksort::decode(const std::string &input,int top)
+{
+	std::string result,inputs=input;
+	std::vector<int> idx(input.size());
+  for (int i = 0; i != idx.size(); ++i) idx[i] = i;
+	std::stable_sort(idx.begin(),idx.end(),
+			[inputs](int i1,int i2)	{return inputs[i1] < inputs[i2];});
+
+	int p = top;
+	for(int i=0;i<input.size();++i) {
+		p = idx[p];
+		result += inputs[p];
+	}
+
+	return result;
+}