题目列表

• 54. 螺旋矩阵

  具体实现

  54. 螺旋矩阵

  class Solution {
    boolean[][] f ;
    int[] dx = new int[]{0, 1, 0, -1};
    int[] dy = new int[]{1, 0, -1, 0};
    public List<Integer> spiralOrder(int[][] matrix) {
        List<Integer> res = new ArrayList<>();
        int m = matrix.length, n = matrix[0].length;
        f = new boolean[m][n];
        int d = 0;
        for(int i = 0, j = 0, t = 0; t < m * n; t++){
            // System.out.println(i + "  " + j);
            res.add(matrix[i][j]);
            f[i][j] = true;
            int a = i + dx[d];
            int b = j + dy[d];
            if(a < 0 || a >= m || b < 0 || b >= n || f[a][b] == true){
                d = (d + 1) % 4;
                a = i + dx[d];
                b = j + dy[d];
            }
            i = a;
            j = b;
        }
        return res;
    }
  }

  class Solution {
    public List<Integer> spiralOrder(int[][] matrix) {
        List<Integer> res = new ArrayList<>();
        int t = 0, b = matrix.length - 1, l = 0, r = matrix[0].length - 1;
        while(t <= b && l <= r){
            if(t == b){
                for(int i = l; i <= r; i++) res.add(matrix[t][i]);
            }else if(l == r){
                for(int i = t; i <= b; i++) res.add(matrix[i][l]);
            }else{
                for(int i = l; i < r; i++) res.add(matrix[t][i]);
                for(int i = t; i < b; i++) res.add(matrix[i][r]);
                for(int i = r; i > l; i--) res.add(matrix[b][i]);
                for(int i = b; i > t; i--) res.add(matrix[i][l]);
            }
            t++; b--;
            l++; r--;
        }
        return res;
    }
  }