|  | 
|  | 1 | +# 1560. Most Visited Sector in  a Circular Track | 
|  | 2 | + | 
|  | 3 | +- Difficulty: Easy. | 
|  | 4 | +- Related Topics: Array, Simulation. | 
|  | 5 | +- Similar Questions: . | 
|  | 6 | + | 
|  | 7 | +## Problem | 
|  | 8 | + | 
|  | 9 | +Given an integer `n` and an integer array `rounds`. We have a circular track which consists of `n` sectors labeled from `1` to `n`. A marathon will be held on this track, the marathon consists of `m` rounds. The `ith` round starts at sector `rounds[i - 1]` and ends at sector `rounds[i]`. For example, round 1 starts at sector `rounds[0]` and ends at sector `rounds[1]` | 
|  | 10 | + | 
|  | 11 | +Return **an array of the most visited sectors** sorted in **ascending** order. | 
|  | 12 | + | 
|  | 13 | +Notice that you circulate the track in ascending order of sector numbers in the counter-clockwise direction (See the first example). | 
|  | 14 | + | 
|  | 15 | +  | 
|  | 16 | +Example 1: | 
|  | 17 | + | 
|  | 18 | + | 
|  | 19 | + | 
|  | 20 | +``` | 
|  | 21 | +Input: n = 4, rounds = [1,3,1,2] | 
|  | 22 | +Output: [1,2] | 
|  | 23 | +Explanation: The marathon starts at sector 1. The order of the visited sectors is as follows: | 
|  | 24 | +1 --> 2 --> 3 (end of round 1) --> 4 --> 1 (end of round 2) --> 2 (end of round 3 and the marathon) | 
|  | 25 | +We can see that both sectors 1 and 2 are visited twice and they are the most visited sectors. Sectors 3 and 4 are visited only once. | 
|  | 26 | +``` | 
|  | 27 | + | 
|  | 28 | +Example 2: | 
|  | 29 | + | 
|  | 30 | +``` | 
|  | 31 | +Input: n = 2, rounds = [2,1,2,1,2,1,2,1,2] | 
|  | 32 | +Output: [2] | 
|  | 33 | +``` | 
|  | 34 | + | 
|  | 35 | +Example 3: | 
|  | 36 | + | 
|  | 37 | +``` | 
|  | 38 | +Input: n = 7, rounds = [1,3,5,7] | 
|  | 39 | +Output: [1,2,3,4,5,6,7] | 
|  | 40 | +``` | 
|  | 41 | + | 
|  | 42 | +  | 
|  | 43 | +**Constraints:** | 
|  | 44 | + | 
|  | 45 | + | 
|  | 46 | +	 | 
|  | 47 | +- `2 <= n <= 100` | 
|  | 48 | +	 | 
|  | 49 | +- `1 <= m <= 100` | 
|  | 50 | +	 | 
|  | 51 | +- `rounds.length == m + 1` | 
|  | 52 | +	 | 
|  | 53 | +- `1 <= rounds[i] <= n` | 
|  | 54 | +	 | 
|  | 55 | +- `rounds[i] != rounds[i + 1]` for `0 <= i < m` | 
|  | 56 | + | 
|  | 57 | + | 
|  | 58 | + | 
|  | 59 | +## Solution | 
|  | 60 | + | 
|  | 61 | +```javascript | 
|  | 62 | +/** | 
|  | 63 | + * @param {number} n | 
|  | 64 | + * @param {number[]} rounds | 
|  | 65 | + * @return {number[]} | 
|  | 66 | + */ | 
|  | 67 | +var mostVisited = function(n, rounds) { | 
|  | 68 | +    var start = rounds[0]; | 
|  | 69 | +    var end = rounds[rounds.length - 1]; | 
|  | 70 | +    if (end >= start) { | 
|  | 71 | +        return Array(end - start + 1).fill(0).reduce((arr, num, i) => { | 
|  | 72 | +            arr.push(start + i); | 
|  | 73 | +            return arr; | 
|  | 74 | +        }, []); | 
|  | 75 | +    } else { | 
|  | 76 | +        var arr1 = Array(n - start + 1).fill(0).reduce((arr, num, i) => { | 
|  | 77 | +            arr.push(start + i); | 
|  | 78 | +            return arr; | 
|  | 79 | +        }, []); | 
|  | 80 | +        var arr2 = Array(end).fill(0).reduce((arr, num, i) => { | 
|  | 81 | +            arr.push(i + 1); | 
|  | 82 | +            return arr; | 
|  | 83 | +        }, []); | 
|  | 84 | +        return arr2.concat(arr1); | 
|  | 85 | +    } | 
|  | 86 | +}; | 
|  | 87 | +``` | 
|  | 88 | + | 
|  | 89 | +**Explain:** | 
|  | 90 | + | 
|  | 91 | +if start <= end, return range[start, end] | 
|  | 92 | + | 
|  | 93 | +else return range[0, end] + range[start, n] | 
|  | 94 | + | 
|  | 95 | +**Complexity:** | 
|  | 96 | + | 
|  | 97 | +* Time complexity : O(n). | 
|  | 98 | +* Space complexity : O(n). | 
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