问题
原题地址： https://leetcode.com/problems/spiral-matrix-ii/
Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.
For example,
Given n = 3,
You should return the following matrix:
[
[ 1, 2, 3 ],
[ 8, 9, 4 ],
[ 7, 6, 5 ]
]
JS 版 148ms 通过结果
/**
* @param {number} n
* @returns {number[][]}
*/
var generateMatrix = function (n) {
var result = [];
var index = 0;
for (; index < n; index++) {
result.push(new Array(n));
}
var i = 0,
j = 0,
directionX = 0,
directionY = 1;
index = 1;
while (index <= Math.pow(n, 2)) {
result[i][j] = index++;
if (directionX === 0 && directionY === 1 && (j === n - 1 || result[i][j + 1] !== undefined)) {
directionX = 1;
directionY = 0;
} else if (directionX === 1 && directionY === 0 && (i === n - 1 || result[i + 1][j] !== undefined)) {
directionX = 0;
directionY = -1;
} else if (directionX === 0 && directionY === -1 && (j === 0 || result[i][j - 1] !== undefined)) {
directionX = -1;
directionY = 0;
} else if (directionX === -1 && directionY === 0 && (i === 0 || result[i - 1][j] !== undefined)) {
directionX = 0;
directionY = 1;
}
i += directionX;
j += directionY;
}
return result;
};