How to swap two integer without temportary variable ? 可以用XOR: public class SwapTwoIntegerWithoutVariable { public static void main(String[] args) { int a = Integer.MAX_VALUE; int b = Integer.MIN_VALUE; a = a^b; b = a^b; a = a^b; System.out.println(“a “+a); System.out.println(“b “+b); } }
Given random generator from 1 – 5 with equal possibility. Design Random generator 1 – 7 设计一个5×5矩阵, 然后把1-7放进去, 多的地方放0. 随机选i和j, 如果选0 就重新选, 如果没有 就返回. import java.util.*; public class RandomGenerator { public int rnd5(){ return new Random().nextInt(5)+1; } public int rnd7() { int[][] m = new int[][]{ {1,2,3,4,5}, {6,7,1,2,3}, {4,5,6,7,1}, {2,3,4,5,6}, {7,0,0,0,0} }; int result = 0; […]