Given a non-negative integer numRows, generate the first numRows of Pascal's triangle.
In Pascal's triangle, each number is the sum of the two numbers directly above it.
Example:
Input: 5 Output: [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ]
/**
* @param {number} numRows
* @return {number[][]}
*/
var generate = function(numRows) {
const result = [];
for (let i = 1; i <= numRows; i++) {
let tmpArr = new Array(i).fill(1);
const lastArr = result[i - 2];
for (let j = 1; j < i - 1; j++) {
tmpArr[j] = lastArr[j - 1] + lastArr[j];
}
result.push(tmpArr);
}
return result;
};
Complexity Analysis
- Time complexity:
O(n^2) - Space complexity:
O(1)