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spiral-matrix.js
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spiral-matrix.js
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// Source : https://leetcode.com/problems/spiral-matrix/
// Author : Han Zichi
// Date : 2015-08-14
/**
* @param {number[][]} matrix
* @return {number[]}
*/
var ans, m, n, hash;
var dir = [[0, 1], [1, 0], [0, -1], [-1, 0]];
function dfs(x, y, k, m, n, matrix, num) {
ans.push(matrix[x][y]);
hash[x][y] = true;
if (num + 1 === m * n)
return;
// next direction
var cur_k;
// next imaging position
var _x = x + dir[k][0]
, _y = y + dir[k][1];
if (_x < 0 || _x >= m || _y < 0 || _y >= n || hash[_x][_y])
// need to turn
cur_k = (k + 1) % 4;
else
cur_k = k;
// next real position
var _x = x + dir[cur_k][0]
, _y = y + dir[cur_k][1];
dfs(_x, _y, cur_k, m, n, matrix, num + 1);
}
var spiralOrder = function(matrix) {
if (matrix.length === 0)
return [];
ans = [],
hash = [],
m = matrix.length,
n = matrix[0].length;
for (var i = 0; i < m; i++)
hash[i] = [];
dfs(0, 0, 0, m, n, matrix, 0);
return ans;
};