原文：
给定 2d 数组，以逆时针螺旋形式打印。 请参阅以下示例。
示例：
input:
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
output:
1 5 9 13 14 15 16 12 8 4 3 2 6 10 11 7
input:
1 2 3 4 5 6
7 8 9 10 11 12
13 14 15 16 17 18
output:
1 7 13 14 15 16 17 18 12 6 5 4 3 2 8 9 10 11
说明：
下面是实现：
c
// c implementation to print
// the counter clock wise
// spiral traversal of matrix
#include
using namespace std;
#define r 4
#define c 4
// function to print the
// required traversal
void counterclockspiralprint(int m,
int n,
int arr[r][c])
{
int i, k = 0, l = 0;
// k - starting row index
// m - ending row index
// l - starting column index
// n - ending column index
// i - iterator
// initialize the count
int cnt = 0;
// total number of
// elements in matrix
int total = m * n;
while (k < m && l < n)
{
if (cnt == total)
break;
// print the first column
// from the remaining columns
for (i = k; i < m; i)
{
cout << arr[i][l] << " ";
cnt ;
}
l ;
if (cnt == total)
break;
// print the last row from
// the remaining rows
for (i = l; i < n; i)
{
cout << arr[m - 1][i] << " ";
cnt ;
}
m--;
if (cnt == total)
break;
// print the last column
// from the remaining columns
if (k < m)
{
for (i = m - 1; i >= k; --i)
{
cout << arr[i][n - 1] << " ";
cnt ;
}
n--;
}
if (cnt == total)
break;
// print the first row
// from the remaining rows
if (l < n)
{
for (i = n - 1; i >= l; --i)
{
cout << arr[k][i] << " ";
cnt ;
}
k ;
}
}
}
// driver code
int main()
{
int arr[r][c] = {{ 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 }};
counterclockspiralprint(r, c, arr);
return 0;
}
java
// java implementation to print
// the counter clock wise
// spiral traversal of matrix
import java.io.*;
class gfg
{
static int r = 4;
static int c = 4;
// function to print the
// required traversal
static void counterclockspiralprint(int m,
int n,
int arr[][])
{
int i, k = 0, l = 0;
/* k - starting row index
m - ending row index
l - starting column index
n - ending column index
i - iterator */
// initialize the count
int cnt = 0;
// total number of
// elements in matrix
int total = m * n;
while (k < m && l < n)
{
if (cnt == total)
break;
// print the first column
// from the remaining columns
for (i = k; i < m; i)
{
system.out.print(arr[i][l] " ");
cnt ;
}
l ;
if (cnt == total)
break;
// print the last row from
// the remaining rows
for (i = l; i < n; i)
{
system.out.print(arr[m - 1][i] " ");
cnt ;
}
m--;
if (cnt == total)
break;
// print the last column
// from the remaining columns
if (k < m)
{
for (i = m - 1; i >= k; --i)
{
system.out.print(arr[i][n - 1] " ");
cnt ;
}
n--;
}
if (cnt == total)
break;
// print the first row
// from the remaining rows
if (l < n)
{
for (i = n - 1; i >= l; --i)
{
system.out.print(arr[k][i] " ");
cnt ;
}
k ;
}
}
}
// driver code
public static void main(string[] args)
{
int arr[][] = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 } };
// function calling
counterclockspiralprint(r, c, arr);
}
}
// this code is contributed by vt_m
python3
# python3 implementation to print
# the counter clock wise
# spiral traversal of matrix
r = 4
c = 4
# function to print
# the required traversal
def counterclockspiralprint(m, n, arr) :
k = 0; l = 0
# k - starting row index
# m - ending row index
# l - starting column index
# n - ending column index
# i - iterator
# initialize the count
cnt = 0
# total number of
# elements in matrix
total = m * n
while (k < m and l < n) :
if (cnt == total) :
break
# print the first column
# from the remaining columns
for i in range(k, m) :
print(arr[i][l], end = " ")
cnt = 1
l = 1
if (cnt == total) :
break
# print the last row from
# the remaining rows
for i in range (l, n) :
print( arr[m - 1][i], end = " ")
cnt = 1
m -= 1
if (cnt == total) :
break
# print the last column
# from the remaining columns
if (k < m) :
for i in range(m - 1, k - 1, -1) :
print(arr[i][n - 1], end = " ")
cnt = 1
n -= 1
if (cnt == total) :
break
# print the first row
# from the remaining rows
if (l < n) :
for i in range(n - 1, l - 1, -1) :
print( arr[k][i], end = " ")
cnt = 1
k = 1
# driver code
arr = [ [ 1, 2, 3, 4 ],
[ 5, 6, 7, 8 ],
[ 9, 10, 11, 12 ],
[ 13, 14, 15, 16 ] ]
counterclockspiralprint(r, c, arr)
# this code is contributed by nikita tiwari
c
// c# implementation to print
// the counter clock wise
// spiral traversal of matrix;
using system;
class gfg
{
static int r = 4;
static int c = 4;
// function to print the required traversal
static void counterclockspiralprint(int m,
int n,
int[,] arr)
{
int i, k = 0, l = 0;
// k - starting row index
// m - ending row index
// l - starting column index
// n - ending column index
// i - iterator
// initialize the count
int cnt = 0;
// total number of elements in matrix
int total = m * n;
while (k < m && l < n)
{
if (cnt == total)
break;
// print the first column from
// the remaining columns
for (i = k; i < m; i)
{
console.write(arr[i,l] " ");
cnt ;
}
l ;
if (cnt == total)
break;
// print the last row from
// the remaining rows
for (i = l; i < n; i)
{
console.write(arr[m - 1, i] " ");
cnt ;
}
m--;
if (cnt == total)
break;
// print the last column from
// the remaining columns
if (k < m) {
for (i = m - 1; i >= k; --i)
{
console.write(arr[i, n - 1] " ");
cnt ;
}
n--;
}
if (cnt == total)
break;
// print the first row from
// the remaining rows
if (l < n)
{
for (i = n - 1; i >= l; --i)
{
console.write(arr[k, i] " ");
cnt ;
}
k ;
}
}
}
// driver code
public static void main()
{
int[,] arr =new int[,] {{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12},
{13, 14, 15, 16}};
// function calling
counterclockspiralprint(r, c, arr);
}
}
// this code is contributed by krv.
php
= $k; --$i)
{
echo $arr[$i][$n - 1] , " ";
$cnt ;
}
$n--;
}
if ($cnt == $total)
break;
// print the first row
// from the remaining rows
if ($l < $n) {
for ($i = $n - 1; $i >= $l; --$i)
{
echo $arr[$k][$i] , " ";
$cnt ;
}
$k ;
}
}
}
// driver code
global $r,$c;
$arr = array(array( 1, 2, 3, 4 ),
array( 5, 6, 7, 8 ),
array( 9, 10, 11, 12 ),
array( 13, 14, 15, 16 ));
echo counterclockspiralprint($r, $c, $arr);
// this code is contributed by anuj_67.
?>
输出：
1 5 9 13 14 15 16 12 8 4 3 2 6 10 11 7
时间复杂度：o(mn)。
替代实现：
python
# python3 implementation to print
# the counter clock wise
# spiral traversal of matrix
#function to print matrix in counterclockwise
def counterclockspiralprint(matrix):
size = len(matrix)
flag = 0
k, i = 0, size
# print all layers one by one
while(i > 0):
# print first column of current layer
for j in range(flag,i):
print(matrix[j][k], end = ' ')
i = i - 1
k = j
# print bottom row and last column
# of current layer
if (i > 0):
for j in range(size - i,i 1):
print(matrix[k][j], end = ' ')
for j in range(k-1,size-i-2,-1):
print(matrix[j][k], end = ' ')
else: break
k = j
i = i-1
# print top row of current layer
if (i > 0):
for j in range(i,size - i-2,-1):
print(matrix[k][j], end = ' ')
k,i = k 1,i 1
flag = flag 1
else: break
# driver code
arr = [ [ 1, 2, 3, 4 ],
[ 5, 6, 7, 8 ],
[ 9, 10, 11, 12 ],
[ 13, 14, 15, 16 ] ]
counterclockspiralprint(arr)
# this code is contributed by srihari r
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