京东2016校招编程题

记得有一个大题，说的是给定一个n*n的矩阵，要求从1开始填充矩阵，最后的矩阵是蛇形的。即如下：

n=3, 7 8 1

6 9 2

5 4 3

n=4, 10 11 12 1

9 16 13 2

8 15 14 3

7 6 5 4

给出代码：

#include <iostream>
#include <vector>
using namespace std;
void snake(int m, vector<vector<int> > &a)
{
int k = m;
int i = 0; int j = 0;
int count = 0;
int l = 0;
while (k >= 0)
{
j = m - 1 - l;
for (i = l; i < m - l; i++)
{
count++;
a[i][j] = count;

}
i = m - 1 - l;
for (j = m - 2 - l; j >= l; j--)
{
count++;
a[i][j] = count;
}
j = l;
for (i = m - 2 - l; i >= l; i--)
{
count++;
a[i][j] = count;
}
i = l;
for (j = l + 1; j < m - 1 - l; j++)
{
count++;
a[i][j] = count;
}
k = k - 2;
l++;
}

}

int  main()
{
int m;
cin >> m;
vector<vector<int> > b(m);
for (int i = 0; i < m; i++)
{
b[i].resize(m);
}
snake(m, b);
for (int i = 0; i < m; i++)
{
for (int j = 0; j < m; j++)
{
cout << b[i][j] << "\t";
}
cout << endl;
}
return 0;
}

结果：

6

16 17 18 19 20 1

15 30 31 32 21 2

14 29 36 33 22 3

13 28 35 34 23 4

12 27 26 25 24 5

11 10 9 8 7 6

请按任意键继续. . .