78 lines
2.3 KiB
C++
78 lines
2.3 KiB
C++
#include "cpp_headers/fcpp.hh"
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bool deck_check(int deck[], int n) {
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for (int i = 0; i < n; i++) {
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// compare deck with number at this position
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// because initial deck is [0,1,2,3,..., n-1]
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if (deck[i] != i) {
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// if a difference is found, return false
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return false;
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}
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}
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// if no problem was found, deck is the original deck
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return true;
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}
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int main() {
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// query the amount of cards that should be shuffled
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int size = enter_int("How many cards do you want to be shuffled? ");
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// only shuffle even number of cards
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if (size <= 0, size % 2 != 0) {
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print("Invalid input, please enter an even number >= 2");
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return 0;
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}
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// initialize the deck of cards
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int deck[size];
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for (int i = 0; i<size; i++) {
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deck[i] = i;
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}
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// initialize a working array
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int newdeck[size];
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// perfect out shuffle
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for (int times = 1; ;times++) {
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// shuffle with perfect out
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for (int i = 0; i<size/2; i++) {
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newdeck[i*2] = deck[i];
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newdeck[i*2+1] = deck[i+size/2];
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}
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// check if newdeck is the original deck
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if (deck_check(newdeck, size)) {
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// print out the amount of iterations needed
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printf("We needed %d perfect out shuffle iterations to get back to the original deck\n", times);
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break;
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} else {
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// otherwise set deck to newdeck
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for (int i = 0; i <size; i++) {
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deck[i] = newdeck[i];
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}
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}
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}
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// reset the deck
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for (int i = 0; i<size; i++) {
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deck[i] = i;
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}
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// perfect in shuffle
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for (int times = 1; ;times++) {
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// shuffle with perfect in
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for (int i = 0; i<size/2; i++) {
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newdeck[i*2] = deck[i+size/2];
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newdeck[i*2+1] = deck[i];
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}
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// check if newdeck is the original deck
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if (deck_check(newdeck, size)) {
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// print out the amount of iterations needed
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printf("We needed %d perfect in shuffle iterations to get back to the original deck\n", times);
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break;
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} else {
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// otherwise set deck to newdeck
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for (int i = 0; i <size; i++) {
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deck[i] = newdeck[i];
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}
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}
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}
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}
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