摩托罗拉笔试
螺旋矩阵输出
递归思路
百度
洗牌
要求严格和原来位置不一样
card类
初始化略
不考虑随机函数的时间复杂度,大概为O[n]
完备性证明用反证
螺旋矩阵输出
递归思路
public int[][] create(int begin, int num) {
int[][] temp = new int[num][num];
if (num == 1) {
temp[0][0] = begin;
} else if (num == 2) {
temp[0][0] = begin;
temp[0][1] = begin + 1;
temp[1][0] = begin + 3;
temp[1][1] = begin + 2;
} else {
int[][] temp1 = create(begin + 4 * num - 4, num - 2);
for (int i = 0; i < num; i++) {
temp[0][i] = begin + i;
}
for (int i = 1; i < num - 1; i++) {
for (int j = 0; j < num; j++) {
if (j == 0) {
temp[i][j] = 4 * num - 4 + begin - i;
} else if (j == num - 1) {
temp[i][j] = begin + num - 1 + i;
} else {
temp[i][j] = temp1[i - 1][j - 1];
}
}
}
for (int i = 0; i < num; i++) {
temp[num - 1][i] = 3 * num - 3 + begin - i;
}
}
return temp;
}
百度
洗牌
要求严格和原来位置不一样
Card[] array = new Card[52];
private void newPork() {
Random r = new Random();
for (int j = 0; j < 52; j++) {
Card c = array[j];
if (c.isRight()) {
continue;
} else {
int i = r.nextInt(51);
if (i != c.site) {//这个很烦,用while()会比较好,
Card temp = c;
array[j] = array[i];
array[j].setNewsite(j);
temp.setNewsite(i);
array[i] = temp;
}
}
}
}
card类
class Card {
int value;
int type;
int old = -1;
int site = -1;
public Card(int value, int type) {
this.value = value;
this.type = type;
}
public boolean isRight() {
if (old == site) {
return false;
} else {
return true;
}
}
public void setOld(int old) {
this.old = old;
}
public void setNewsite(int _newsite) {
this.site = _newsite;
}
}
初始化略
不考虑随机函数的时间复杂度,大概为O[n]
完备性证明用反证