59. 螺旋矩阵 II

C++

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class Solution {
public:
    vector<vector<int>> generateMatrix(int n) {
        vector<vector<int>> res(n, vector<int>(n, 0)); // 使用vector定义一个二维数组，全部元素初始化为零
        int di[] = {0, 1, 0, -1};
        int dj[] = {1, 0, -1, 0};
        for(int i = 0, j = 0, d = 0, k = 1;k <= n * n;k++){
            res[i][j] = k;
            int iNext = i + di[d];
            int jNext = j + dj[d];
            if(iNext < 0 || iNext >= n || jNext < 0 || jNext >= n || res[iNext][jNext]){
                d = (d + 1) % 4;
                iNext = i + di[d];
                jNext = j + dj[d];
            }  
            i = iNext;
            j = jNext;
        }
        return res;
    }
};

54. 螺旋矩阵

C++