Problem
Given a 2D integer array nums, return **all elements of *nums* in diagonal order as shown in the below images**.
Example 1:
Input: nums = [[1,2,3],[4,5,6],[7,8,9]]
Output: [1,4,2,7,5,3,8,6,9]
Example 2:
Input: nums = [[1,2,3,4,5],[6,7],[8],[9,10,11],[12,13,14,15,16]]
Output: [1,6,2,8,7,3,9,4,12,10,5,13,11,14,15,16]
Constraints:
1 <= nums.length <= 1051 <= nums[i].length <= 1051 <= sum(nums[i].length) <= 1051 <= nums[i][j] <= 105
Solution
/**
* @param {number[][]} nums
* @return {number[]}
*/
var findDiagonalOrder = function(nums) {
var groups = [];
for (var i = nums.length - 1 ; i >= 0; i--) {
for (var j = 0; j < nums[i].length; j++) {
groups[i + j] = groups[i + j] || [];
groups[i + j].push(nums[i][j]);
}
}
return [].concat(...groups);
};
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).