LC59. 螺旋矩阵 II
class Solution {
public int[][] generateMatrix(int n) {
int maxNum = n * n, curNum = 1;
int[][] matrix = new int[n][n];
int[][] directions = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
int row = 0, column = 0, directionIndex = 0;
while (curNum <= maxNum) {
matrix[row][column] = curNum;
curNum++;
int nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];
if (nextRow < 0 || nextRow >= n || nextColumn < 0 || nextColumn >= n || matrix[nextRow][nextColumn] != 0) {
directionIndex = (directionIndex + 1) % 4; //顺时针旋转
}
row += directions[directionIndex][0];
column += directions[directionIndex][1];
}
return matrix;
}
}
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