C # generate a random index list,

C # generate a random index list,

/// <Summary> /// generate a random index list /// </summary> /// <param name = "maxNumber"> </param> /// <returns> </returns> private static List <int> CreateRandomNumbers (int maxNumber) {var array = new int [maxNumber]; for (var I = 0; I <maxNumber; I ++) {array [I] = I ;} var rnd = new Random (); for (var I = 0; I <maxNumber; I ++) {var index = rnd. next (0, maxNumber); if (I! = Index) {var tmpval = array [I]; array [I] = array [index]; array [index] = tmpval ;}} var list = new List <int> (); for (var I = 0; I <maxNumber; I ++) {list. add (array [I]);} return list ;} /// <summary> /// generate a random index list /// </summary> /// <param name = "maxNumber"> </param> /// <returns> </returns> private static List <int> CreateRandomNumbers2 (int maxNumber) {List <int> list = new List <int> (); Random rd = New Random (); while (list. Count () <maxNumber) {int I = rd. Next (0, maxNumber); if (! List. contains (I) {list. add (I) ;}} return list ;} /// <summary> /// generate a random index list /// </summary> /// <param name = "maxNumber"> </param> /// <returns> </returns> private static List <int> CreateRandomNumbers2 (int maxNumber) {var array = new int [maxNumber, 2]; var index = maxNumber-1; var rnd = new Random (); while (index> 0) {array [index, 0] = index; array [index, 1] = rnd. next (0, maxNumber); index --;} var list = new List <int> (); for (var I = 0; I <maxNumber; I ++) {for (var j = I + 1; j <maxNumber; j ++) {if (array [I, 1]> array [j, 1]) {var tIndex = array [I, 0]; var tValue = array [I, 1]; array [I, 0] = array [j, 0]; array [I, 1] = array [j, 1]; array [j, 0] = tIndex; array [j, 1] = tValue ;}}for (var I = 0; I <maxNumber; I ++) {list. add (array [I, 0]);} return list ;}

　　

The first is the fastest, the second is the second, and the third is the slowest.