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leetcode_0054_Spiral_Matrix.java
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175 lines (170 loc) · 6.3 KB
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import java.util.*;
/**
* Runtime: 0 ms, faster than 100.00% of Java online submissions for Spiral Matrix.
* Memory Usage: 38.3 MB, less than 9.24% of Java online submissions for Spiral Matrix.
*/
class SprialMatrix {
public List<Integer> spiralOrder(int[][] matrix) {
int row = matrix.length, col = matrix[0].length;
List<Integer> ret = new ArrayList<>();
int[][] record = new int[row][col];
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
record[i][j] = 0;
}
}
int count = 0, direction = 0, i = 0, j = 0;
ret.add(matrix[i][j]);
record[i][j] = 1;
while (count < row * col) {
switch (direction) {
case 0:
if (j + 1 > col - 1) {
if (i + 1 > row - 1 || record[i + 1][j] != 0) {
return ret;
} else {
i++;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
if (record[i][j + 1] != 0) {
if (i + 1 > row - 1 || record[i + 1][j] != 0) {
return ret;
} else {
i++;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
j++;
count++;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
}
break;
case 1:
if (i + 1 > row - 1) {
if (j - 1 < 0 || record[i][j - 1] != 0) {
return ret;
} else {
j--;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
if (record[i + 1][j] != 0) {
if (j - 1 < 0 || record[i][j - 1] != 0) {
return ret;
} else {
j--;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
i++;
count++;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
}
break;
case 2:
if (j - 1 < 0) {
if (i - 1 < 0 || record[i - 1][j] != 0) {
return ret;
} else {
i--;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
if (record[i][j - 1] != 0) {
if (i - 1 < 0 || record[i - 1][j] != 0) {
return ret;
} else {
i--;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
j--;
count++;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
}
break;
case 3:
if (i - 1 < 0) {
if (j + 1 > col - 1 || record[i][j + 1] != 0) {
return ret;
} else {
j++;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
if (record[i - 1][j] != 0) {
if (j + 1 > col - 1 || record[i][j + 1] != 0) {
return ret;
} else {
j++;
count++;
direction = (direction + 1) % 4;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
} else {
i--;
count++;
ret.add(matrix[i][j]);
record[i][j] = 1;
}
}
break;
}
}
return ret;
}
// public static void main(String[] args) {
// int[][] matrix = {
// {1, 2, 3},
// {4, 5, 6},
// {7, 8, 9}
// };
//
// SprialMatrix sm1 = new SprialMatrix();
//
// List<Integer> ret = sm1.spiralOrder(matrix);
// for (int i: ret) {
// System.out.println(i);
// }
//
// int[][] matrix2 = {
// {1, 2, 3, 4},
// {5, 6, 7, 8},
// {9, 10, 11, 12}
// };
//
// List<Integer> ret2 = sm1.spiralOrder(matrix2);
// for (int i: ret2) {
// System.out.println(i);
// }
// }
}