Java实现螺旋矩阵的示例

class Solution {
  public List<Integer> spiralOrder(int[][] matrix) {
    List<Integer> result = new LinkedList<>();
    if(matrix.length==0)  return result;
    int upBound = 0;
    int rightBound = matrix[0].length-1;
    int leftBound = 0;
    int downBound = matrix.length-1;
    while(true){
      for(int i=leftBound; i<=rightBound; ++i)  
        result.add(matrix[upBound][i]);
      if(++upBound>downBound) break;
      for(int i=upBound; i<=downBound; ++i)  
        result.add(matrix[i][rightBound]);
      if(--rightBound<leftBound) break;
      for(int i=rightBound; i>=leftBound; --i)  
        result.add(matrix[downBound][i]);
      if(--downBound<upBound) break;
      for(int i=downBound; i>=upBound; --i)  
        result.add(matrix[i][leftBound]);
      if(++leftBound>rightBound) break;
    }
    return result;
  }
}