题意

54. 螺旋矩阵

题解

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        int m = matrix.size(), n = matrix[0].size();
        int cnt = m * n;
        vector<int> ans;
        int left = 0, right = n - 1, up = 0, down = m - 1;
        while (cnt) {
            for(int j = left; j <= right; j++) {
                ans.push_back(matrix[up][j]);
                cnt--;
                if (cnt == 0) break;
            }
            if (cnt == 0) break;
            up++;
            for (int i = up; i <= down; i++) {
                ans.push_back(matrix[i][right]);
                cnt--;
                if (cnt == 0) break;
            }
            if (cnt == 0) break;
            right--;
            for (int j = right; j >= left; j--) {
                ans.push_back(matrix[down][j]);
                cnt--;
                if (cnt == 0) break;
            }
            if (cnt == 0) break;
            down--;
            for (int i = down; i >= up; i--) {
                ans.push_back(matrix[i][left]);
                cnt--;
                if (cnt == 0) break;
            }
            if (cnt == 0) break;
            left++;
        }
        return ans;
    }
};