蓝桥杯：基础练习 回形取数

基础练习 回形取数

时间限制：1.0s 内存限制：512.0MB

问题描述

　　回形取数就是沿矩阵的边取数，若当前方向上无数可取或已经取过，则左转90度。一开始位于矩阵左上角，方向向下。

输入格式

　　输入第一行是两个不超过200的正整数m, n，表示矩阵的行和列。接下来m行每行n个整数，表示这个矩阵。

输出格式

　　输出只有一行，共mn个数，为输入矩阵回形取数得到的结果。数之间用一个空格分隔，行末不要有多余的空格。

样例输入

3 3

1 2 3

4 5 6

7 8 9

样例输出

1 4 7 8 9 6 3 2 5

样例输入

3 2

1 2

3 4

5 6

样例输出

1 3 5 6 4 2

方法1：

import java.util.Scanner;

public class Main{

private static void printArray(int m, int n, int[][] array){
int mark = 0;
int sum = (m > n ? n : m) / 2;
while(mark <= sum){
for(int i = mark; i < m - mark; i++){ // down: col is stable and col = mark.
if(array[i][mark] != -1){
System.out.print(array[i][mark] + " ");
array[i][mark] = -1;
}
}
for(int i = mark + 1; i < n - mark; i++){ // right: row is stable and row = mark + 1.
if(array[m - mark - 1][i] != -1){
System.out.print(array[m - mark - 1][i] + " ");
array[m - mark - 1][i] = -1;
}
}
for(int i = m - 1 - mark - 1; i >= mark; i--){ // up: col is stable and col = m - 1 - mark - 1.
if(array[i][n - mark - 1] != -1){
System.out.print(array[i][n - mark - 1] + " ");
array[i][n - mark - 1] = -1;
}
}
for(int i = n - 1 - mark - 1; i > mark; i--){ // left: row is stable and row = n - 1 - mark - 1.
if(array[mark][i] != -1){
System.out.print(array[mark][i] + " ");
array[mark][i] = -1;
}
}
mark ++;
}
}

public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int m = sc.nextInt();
int n = sc.nextInt();
int[][] array = new int[m]
;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
array[i][j] = sc.nextInt();
}
}
printArray(m, n, array);
}
}

方法2：

import java.util.Scanner;

public class Main{

public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int mc = sc.nextInt();
int nr = sc.nextInt();
int[][] array = new int[mc][nr];
for (int i = 0; i < mc; i++) {
for (int j = 0; j < nr; j++) {
array[i][j] = sc.nextInt();
}
}
int count = 0;
int circlecount = 0;
int i, j, x = 0, y = 0;
int m = mc;
int n = nr;
int number = 1;
System.out.print(array[0][0]);
array[0][0] = -1;
for (i = 0, j = 0; number < mc * nr;) {
if (i < m - 1 && j == nr - n) { // down
if (array[i][j] != -1) {
System.out.print(" " + array[i][j]);
array[i][j] = -1;
number++;
}
i++;
} else if (i == m - 1 && j != n - 1) { // right
if (array[i][j] != -1) {
System.out.print(" " + array[i][j]);
array[i][j] = -1;
number++;
}
j++;
} else if (j == n - 1 && i > mc - m) { // up
if (array[i][j] != -1) {
System.out.print(" " + array[i][j]);
array[i][j] = -1;
number++;
}
i--;
} else if (j > nr - n && i == mc - m) { // left
if (array[i][j] != -1) {
System.out.print(" " + array[i][j]);
array[i][j] = -1;
number++;
}
j--;
} else {
if (array[i][j] != -1) {
System.out.print(" " + array[i][j]);
array[i][j] = -1;
number++;
}
i++;
}
count++;
if (count == 2 * (m + n) - 4) {
circlecount++;
j = circlecount;
i = circlecount;
m--;
n--;
count = 0;
}
}
}
}

此题总是有三组测试数据超时，欢迎大家积极评论