LeetCode:Spiral Matrix II

标签：algorithm   leetcode   

题目描述：

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

For example,
Given n = 3,

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

思路分析：四个for循环分别控制四个方向上数字的填入。

代码：

vector<vector<int> > Solution::generateMatrix(int n)
{
    vector<vector<int> > matrix;
    vector<int> line;
    int i,j,k;
    int count = 1;
    for(i = 0;i < n;i++)
    {
        for(j = 0;j < n;j++)
            line.push_back(0);
        matrix.push_back(line);
        line.clear();
    }
    for(i = 0;i*2 < n;i++)
    {
        for(j = i,k = i;k < n - i - 1;k++)
            matrix[j][k] = count++;
        for(j = i,k = n - 1 - i;j < n - i - 1;j++)
            matrix[j][k] = count++;
        for(j = n - i - 1,k = n - i - 1;k > i;k--)
            matrix[j][k] = count++;
        for(j = n - 1 - i,k = i;j > i;j--)
            matrix[j][k] = count++;
    }
    if(n % 2 == 1)
        matrix[n/2][n/2] = count++;
    return matrix;
}

LeetCode:Spiral Matrix II

标签：algorithm   leetcode   

原文地址：http://blog.csdn.net/yao_wust/article/details/42169519