Algorithm --> 顺序打印矩阵

顺序打印矩阵

思路

参考代码

#include <iostream>
using namespace std;
void printNumAsClockwise(int a[][4], int row, int col)
{
    if (row < 1 || col < 1)
        return;
    int up = 0, down = row -1, left = 0, right = col -1;
    int i = 0;
    while(up <= down && left <= right)
    {
        for(i = left; i <= right; ++i)
            cout << a[up][i] << " ";
        ++up;

        for(i = up; i <= down; ++i)
            cout << a[i][right] << " ";
        --right;

        for(i = right; i >= left; --i)
            cout << a[down][i] << " ";
        --down;

        for(i = down; i >= up; --i)
            cout << a[i][left] << " ";
        ++left;

    }
    cout << endl;
}

int main()
{
    int a[][4] = {{1,2,3,4}, {5,6,7,8}, {9,10,11,12}, {13,14,15,16}};
    cout << sizeof(a) / sizeof(int) << endl;
    printNumAsClockwise(a, 4, 4);
};

二维数组可以用一维来代替

#include <iostream>
using namespace std;
void printNumAsClockwise(int *a, int row, int col)
{
    if (row < 1 || col < 1)
        return;
    int up = 0, down = row -1, left = 0, right = col -1;
    int i = 0;
    while(up <= down && left <= right)
    {
        for(i = left; i <= right; ++i)
            cout << a[up * col + i] << " ";
        ++up;

        for(i = up; i <= down; ++i)
            cout << a[i * col + right] << " ";
        --right;

        for(i = right; i >= left; --i)
            cout << a[down * col + i] << " ";
        --down;

        for(i = down; i >= up; --i)
            cout << a[i * col + left] << " ";
        ++left;

    }
    cout << endl;
}

int main()
{
    int a[][4] = {{1,2,3,4}, {5,6,7,8}, {9,10,11,12}, {13,14,15,16}};
    cout << sizeof(a) / sizeof(int) << endl;
    printNumAsClockwise((int*)a, 4, 4);
};

注意

注意判别参数符合范围

if (row < 1 || col < 1)
        return;

结果

16
1 2 3 4 8 12 16 15 14 13 9 5 6 7 11 10