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backtracking (Array permutation)
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‎Algorithms/Backtracking (Array Permutation)/Backtracking (Array Permutation).cbp‎

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<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
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<CodeBlocks_project_file>
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<FileVersion major="1" minor="6" />
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<Project>
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<Option title="Backtracking (Array Permutation)" />
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<Option pch_mode="2" />
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<Option compiler="gcc" />
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<Build>
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<Target title="Debug">
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<Option output="bin/Debug/Backtracking (Array Permutation)" prefix_auto="1" extension_auto="1" />
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<Option object_output="obj/Debug/" />
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<Option type="1" />
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<Option compiler="gcc" />
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<Compiler>
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<Add option="-g" />
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</Compiler>
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</Target>
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<Target title="Release">
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<Option output="bin/Release/Backtracking (Array Permutation)" prefix_auto="1" extension_auto="1" />
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<Option object_output="obj/Release/" />
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<Option type="1" />
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<Option compiler="gcc" />
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<Compiler>
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<Add option="-O2" />
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</Compiler>
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<Linker>
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<Add option="-s" />
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</Linker>
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</Target>
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</Build>
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<Compiler>
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<Add option="-Wall" />
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<Add option="-fexceptions" />
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</Compiler>
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<Unit filename="main.cpp" />
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<Extensions>
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<code_completion />
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<envvars />
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<debugger />
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<lib_finder disable_auto="1" />
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</Extensions>
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</Project>
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</CodeBlocks_project_file>

‎Algorithms/Backtracking (Array Permutation)/Backtracking (Array Permutation).layout‎

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<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
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<CodeBlocks_layout_file>
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<FileVersion major="1" minor="0" />
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<ActiveTarget name="Debug" />
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<File name="main.cpp" open="1" top="1" tabpos="1" split="0" active="1" splitpos="0" zoom_1="0" zoom_2="0">
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<Cursor>
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<Cursor1 position="3164" topLine="66" />
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</Cursor>
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</File>
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</CodeBlocks_layout_file>

‎Algorithms/Backtracking (Array Permutation)/bin/Debug/Backtracking (Array Permutation).exe‎

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‎Algorithms/Backtracking (Array Permutation)/main.cpp‎

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#include <iostream>
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#include <vector>
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using namespace std;
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/*
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Permutation of an array using the backtracking technique which
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finds all possible solutions without repeating.
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*/
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ostream& operator << (ostream& stream, const vector<int>& v) {
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for (int i = 0; i < (int)v.size(); i++) {
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stream << v[i] << " ";
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}
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return stream;
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}
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void permutation(vector<int>& v, int index, int arraySize, string space = "") {
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cout << space << "permutation(v, " << index << ", " << arraySize << ")" << endl;
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/*
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permutation([1,2,3], 0, 3, "")
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i == 0
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swap(array[0], array[0]);
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permutation([1,2,3], 1, 3, "") -> index + 1
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i = 1
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swap(array[1], array[1]);
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permutation([1,2,3], 2, 3, "") -> index + 1
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base case ->> print([1,2,3])
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swap(array[1], array[1]); -> ->> [1,2,3] again (backtracking)
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i = 2
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swap(array[1], array[2]);
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permutation([1,3,2], 2, 3, "") -> index + 1
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base case ->> print([1,3,2])
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swap(array[1], array[2]); ->> [1,2,3] again (backtracking)
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i = 3
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break loop;
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i == 1
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swap(array[0], array[1]);
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permutation([2,1,3], 1, 3, "") -> index + 1
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i = 1
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swap(array[1], array[1]);
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permutation([2,1,3], 2, 3, "") -> index + 1
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base case ->> print([2,1,3])
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swap(array[1], array[1]); ->> [2,1,3] again (backtracking)
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i = 2
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swap(array[1], array[2]);
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permutation([2,3,1], 2, 3, "") -> index + 1
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base case ->> print([2,3,1])
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swap(array[1], array[2]); ->> [2,1,3] again (backtracking)
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i = 3
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break loop;
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i == 2
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swap(array[0], array[2]);
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permutation([3,1,2], 1, 3, "") -> index + 1
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i = 1
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swap(array[1], array[1]);
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permutation([3,1,2], 2, 3, "") -> index + 1
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base case ->> print([3,1,2])
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swap(array[1], array[1]); ->> [3,1,2] again (backtracking)
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i = 2
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swap(array[1], array[2]);
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permutation([3,2,1], 2, 3, "") -> index + 1
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base case ->> print([3,2,1])
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swap(array[1], array[2]); ->> [3,1,2] again (backtracking)
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i = 3
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break loop;
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i == 3
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break loop;
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finish function
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*/
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// Base case
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if(index == arraySize - 1) {
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cout << "->>>> " << v << endl;
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} else {
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for (int i = index; i < arraySize; i++) {
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swap(v[index], v[i]);
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permutation(v, index + 1, arraySize, space + " ");
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swap(v[index], v[i]); // Backtrack phase (reordering array)
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}
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}
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}
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int main()
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{
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vector<int> v = {1,2,3};
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permutation(v, 0, 3);
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return 0;
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}

‎Algorithms/Backtracking (Array Permutation)/obj/Debug/main.o‎

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