/// <summary>/// 輸出一個數組的全排列/// </summary>/// <param name="array"></param>private static void PrintFullPermutation(int[] array){ //0.合法性校驗 if (array == null || array.Length == 0) {  return; } //1.復制一個新數組：修改時在臨時數組中修改 int[] temp = new int[array.Length]; for (int i = 0; i < array.Length; i++) {  temp[i] = array[i]; } //2.將新數組升序排列 int itemp; for (int i = 0; i < temp.Length; i++) {  for (int j = i; j < temp.Length; j++)  {   itemp = array[i];   array[i] = array[j];   array[j] = itemp;  } } //3.依次尋找并打印全排序 PrintArray(temp); while (!isDesc(temp)) {  FindNextArray(temp);  PrintArray(temp); }}/// <summary>/// 打印數組/// </summary>/// <param name="array">數組</param>private static void PrintArray(int[] array){ for (int i = 0; i < array.Length; i++) {  Console.Write(array[i].ToString() + '/t'); } Console.WriteLine();}/// <summary>/// 判斷一個數組內元素是否降序排列/// </summary>/// <param name="array">數組</param>/// <returns></returns>private static bool isDesc(int[] array){ int temp=array[0]; for (int i = 1; i < array.Length; i++) {  if (array[i] > array[i - 1])  {   return false;  } } return true;}/// <summary>/// 找到下一組排列/// </summary>/// <param name="array"></param>private static void FindNextArray(int[] array){ //1.找出數組的最大值 int max = array[0]; for (int i = 1; i < array.Length; i++) {  if (max < array[i])  {   max = array[i];  } } //2.從后向前找：找到第一組后數大于前數，以后數位置為signer int signer = array.Length - 1; for (int i = array.Length - 1; i > 0; i--) {  if (array[i] > array[i - 1])  {   signer = i;   break;  } } //3.從signer向后找：找到大于且最接近于array[signer-1]的數array[t] int t = signer; for (int i = signer; i < array.Length; i++) {  if (array[i] > array[signer - 1] && array[i] < max)  {   t = i;   max = array[t];  } } //4.將找到的array[t]和array[signer-1]互換 int temp = array[t]; array[t] = array[signer - 1]; array[signer - 1] = temp; //5.為signer之后的元素升序排序 for (int i = signer; i < array.Length; i++) {  for (int j = i + 1; j < array.Length; j++)  {   if (array[i] > array[j])   {    temp = array[i];    array[i] = array[j];    array[j] = temp;   }  } }}

static void Main(string[] args){ //求1234四個數字的全排列 int[] array = new int[] { 1, 2, 3, 4 }; PrintFullPermutation(array); Console.ReadLine();}