leetcode ---- 螺旋矩阵

解题思路：按照图示思路模拟过程进行

55. 54. 螺旋矩阵

        vector<vector<int>> generateMatrix(int n) {
        // 创建二维矩阵
        vector<vector<int>> matrix(n);
        for (int i = 0; i < matrix.size(); i++)
            matrix[i].resize(n);
        // 上下左右
        int u = 0;
        int d = n - 1;
        int l = 0;
        int r = n - 1;
        int num = 1;
        
        while (true) {
            // 上
            for (int i = l; i <= r; i++) matrix[u][i] = num++;
            if (u++ >= d) break;
            // 右
            for (int i = u; i <= d; i++) matrix[i][r] = num++;
            if (r-- <= l) break;
            // 下
            for (int i = r; i >= l; i--) matrix[d][i] = num++;
            if (d-- <= u) break;
            // 左
            for (int i = d; i >= u; i--) matrix[i][l] = num++;
            if (l++ >= r) break;
        }
        return matrix;
        }

59.螺旋矩阵II

vector<int> spiralOrder(vector<vector<int>>& matrix) {

        vector<int> res;
        // 上下左右
        int u = 0;
        int d = matrix.size() - 1;
        int l = 0;
        int r = matrix[0].size() - 1;
        int num = 1;

        while (true)
        {
            for (int i = l; i <= r; i++)
            {
                res.emplace_back(matrix[u][i]);
            }
            if(u++ >= d) break;

            for (int i = u; i <= d; i++)
            {
                res.emplace_back(matrix[i][r]);
            }
            if (r-- <= l) break;

            for (int i = r; i >= l; i--)
            {
                res.emplace_back(matrix[d][i]);
            }
            if (d-- <= u) break;

            for (int i = d; i >= u; i--)
            {
                res.emplace_back(matrix[i][l]);
            }
            if (l++ >= r) break;
        }
        return res;
    }