以反向波形打印矩阵
给定一个矩阵，以反向波形打印它。
例子 ：
Input : 1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
Output : 4 8 12 16 15 11 7 3 2 6 10 14 13 9 5 1
Input : 1 9 4 10
3 6 90 11
2 30 85 72
6 31 99 15
Output : 10 11 72 15 99 85 90 4 9 6 30 31 6 2 3 1方法：要获得给定矩阵的反向波形，我们首先向下打印矩阵最后一列的元素，然后向上打印倒数第二列的元素，然后打印倒数第三列的元素向下等。例如 1，流程如下：
下面是打印矩阵的反向波形的实现：
C++
// C++ implementation to print
// reverse wave form of matrix
#include
using namespace std;
#define R 4
#define C 4
// function to print reverse wave
// form for a given matrix
void WavePrint(int m, int n, int arr[R][C])
{
int i, j = n - 1, wave = 1;
/* m - Ending row index
n - Ending column index
i, j - Iterator
wave - for Direction
wave = 1 - Wave direction down
wave = 0 - Wave direction up */
while (j >= 0) {
// Check whether to go in
// upward or downward
if (wave == 1) {
// Print the element of the matrix
// downward since the value of wave = 1
for (i = 0; i < m; i++)
cout << arr[i][j] << " ";
wave = 0;
j--;
}
else {
// Print the elements of the
// matrix upward since the value
// of wave = 0
for (i = m - 1; i >= 0; i--)
cout << arr[i][j] << " ";
wave = 1;
j--;
}
}
}
// driver function
int main()
{
int arr[R][C] = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 } };
WavePrint(R, C, arr);
return 0;
} Java
// Java implementation to print
// reverse wave form of matrix
import java.io.*;
class GFG
{
static int R = 4;
static int C = 4;
// function to print reverse wave
// form for a given matrix
static void WavePrint(int m, int n, int arr[][])
{
int i, j = n - 1, wave = 1;
// m- Ending row index
//n - Ending column index
//i, j - Iterator
//wave - for Direction
//wave = 1 - Wave direction down
//wave = 0 - Wave direction up */
while (j >= 0)
{
// Check whether to go in
// upward or downward
if (wave == 1)
{
// Print the element of the matrix
// downward since the value of wave = 1
for (i = 0; i < m; i++)
System.out.print(arr[i][j] +" ");
wave = 0;
j--;
}
else {
// Print the elements of the
// matrix upward since the value
// of wave = 0
for (i = m - 1; i >= 0; i--)
System.out.print( arr[i][j] + " ");
wave = 1;
j--;
}
}
}
// Driver function
public static void main (String[] args)
{
int arr[][] = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 } };
WavePrint(R, C, arr);
}
}
// This code is contributed by vt_mPython3
# Python3 implementation to print
# reverse wave form of matrix
R = 4
C = 4
# function to print reverse wave
# form for a given matrix
def wavePrint(m, n, arr):
j = n - 1
wave = 1
# m - Ending row index
# n - Ending column index
# i, j - Iterator
# wave - for Direction
# wave = 1 - Wave direction down
# wave = 0 - Wave direction up
while j >= 0:
# Check whether to go in
# upward or downward
if wave == 1:
# Print the element of the
# matrix downward since the
# value of wave = 1
for i in range(m):
print(arr[i][j], end = " "),
wave = 0
j -= 1
else:
# Print the elements of the
# matrix upward since the
# value of wave = 0
for i in range(m - 1, -1, -1):
print(arr[i][j], end = " "),
wave = 1
j -= 1
# Driver code
arr = [ [ 1, 2, 3, 4 ],
[ 5, 6, 7, 8 ],
[ 9, 10, 11, 12 ],
[ 13, 14, 15, 16 ] ]
wavePrint(R, C, arr)
# This code is contributed by
# Upendra Singh BartwalC#
// C# implementation to print
// reverse wave form of matrix
using System;
class GFG {
static int R = 4;
static int C = 4;
// function to print reverse wave
// form for a given matrix
static void WavePrint(int m, int n, int [,]arr)
{
int i, j = n - 1, wave = 1;
// m- Ending row index
// n - Ending column index
// i, j - Iterator
// wave - for Direction
// wave = 1 - Wave direction down
// wave = 0 - Wave direction up */
while (j >= 0)
{
// Check whether to go in
// upward or downward
if (wave == 1) {
// Print the element of the
// matrix downward since the
// value of wave = 1
for (i = 0; i < m; i++)
Console.Write(arr[i,j] + " ");
wave = 0;
j--;
}
else {
// Print the elements of the
// matrix upward since the value
// of wave = 0
for (i = m - 1; i >= 0; i--)
Console.Write( arr[i,j] + " ");
wave = 1;
j--;
}
}
}
// Driver function
public static void Main ()
{
int [,]arr = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 } };
WavePrint(R, C, arr);
}
}
// This code is contributed by vt_m.PHP
= 0)
{
// Check whether to go in
// upward or downward
if ($wave == 1)
{
// Print the element of the
// matrix downward since the
// value of wave = 1
for ($i = 0; $i < $m; $i++)
echo $arr[$i][$j] , " ";
$wave = 0;
$j--;
}
else
{
// Print the elements of
// the matrix upward since
// the value of wave = 0
for ($i = $m - 1; $i >= 0; $i--)
echo $arr[$i][$j] , " ";
$wave = 1;
$j--;
}
}
}
// Driver Code
$arr = array(array(1, 2, 3, 4),
array(5, 6, 7, 8),
array(9, 10, 11, 12),
array(13, 14, 15, 16));
WavePrint($R, $C, $arr);
// This code is contributed by ajit
?>Javascript
输出：
4 8 12 16 15 11 7 3 2 6 10 14 13 9 5 1 复杂性分析
- 时间复杂度：O(N 2 )
- 辅助空间： O(1)