【Leetcode】面试题29. 顺时针打印矩阵

 

class Solution {
    public int[] spiralOrder(int[][] matrix) {
        if(matrix == null || matrix.length == 0){
            return new int[]{};
        }
        int index = 0;
        int l = 0, r = matrix[0].length-1, t = 0, b = matrix.length-1;
                int[] ans = new int[(r+1) * (b+1)];
        while(true){
            for(int i = l; i <= r; i++) ans[index++] = matrix[l][i];
            if(++t > b) break;
            for(int i = t; i <= b; i++) ans[index++] = matrix[i][r];
            if(--r < l) break;
            for(int i = r; i >= l; i--) ans[index++] = matrix[b][i];
            if(--b < t) break;
            for(int i = b; i >= t; i--) ans[index++] = matrix[i][l];
            if(++l > r) break;
        }
        return ans;
    }
}