2849. Determine if a Cell Is Reachable at a Given Time

Problem

You are given four integers sx, sy, fx, fy, and a non-negative integer t.

In an infinite 2D grid, you start at the cell (sx, sy). Each second, you must move to any of its adjacent cells.

Return true **if you can reach cell *(fx, fy) after exactly*** t *seconds*, *or* false otherwise.

A cell's adjacent cells are the 8 cells around it that share at least one corner with it. You can visit the same cell several times.

  Example 1:

Input: sx = 2, sy = 4, fx = 7, fy = 7, t = 6
Output: true
Explanation: Starting at cell (2, 4), we can reach cell (7, 7) in exactly 6 seconds by going through the cells depicted in the picture above. 

Example 2:

Input: sx = 3, sy = 1, fx = 7, fy = 3, t = 3
Output: false
Explanation: Starting at cell (3, 1), it takes at least 4 seconds to reach cell (7, 3) by going through the cells depicted in the picture above. Hence, we cannot reach cell (7, 3) at the third second.

  Constraints:

• 1 <= sx, sy, fx, fy <= 109

• 0 <= t <= 109

Solution

/**
 * @param {number} sx
 * @param {number} sy
 * @param {number} fx
 * @param {number} fy
 * @param {number} t
 * @return {boolean}
 */
var isReachableAtTime = function(sx, sy, fx, fy, t) {
    const x = Math.abs(sx - fx);
    const y = Math.abs(sy - fy);
    if (sx === fx && sy === fy && t === 1) {
        return false;
    }
    return Math.max(x, y) <= t;
};

Explain:

nope.

Complexity:

• Time complexity : O(1).
• Space complexity : O(1).