54. Spiral Matrix

就是实现题。于是我用了一个半小时 = =心好累

如果layer数是奇数的时候要多处理一下

    public List<Integer> spiralOrder(int[][] matrix) {
        List<Integer> res = new ArrayList<Integer>();
        if(matrix == null || matrix.length == 0) {
            return res;
        }
        int row = matrix.length;//row
        int col = matrix[0].length;//col
        int min = Math.min(row, col);
        int layer = min/2;
        for(int level = 0; level < layer; level++) {
            for(int i = level; i < col-1-level; i++) {
                res.add(matrix[level][i]);
            }
            for(int i = level; i < row-1-level; i++) {
                res.add(matrix[i][col-1-level]);
            }
            for(int i = level; i < col-1-level; i++) {
                res.add(matrix[row-1-level][col-1-i]);
            }
            for(int i = level; i < row-1-level; i++) {
                res.add(matrix[row-1-i][level]);
            }
        }
        if(min % 2 == 1) {
            if(min == col) {
                for(int i = layer; i < row-layer; i++) {
                    res.add(matrix[i][layer]);
                }
            } else {
                for(int i = layer; i < col-layer; i++) {
                    res.add(matrix[layer][i]);
                }
            }
        }
        System.out.println(res);
        return res;
    }