|
| 1 | +# 2678. Number of Senior Citizens |
| 2 | + |
| 3 | +- Difficulty: Easy. |
| 4 | +- Related Topics: Array, String. |
| 5 | +- Similar Questions: . |
| 6 | + |
| 7 | +## Problem |
| 8 | + |
| 9 | +You are given a **0-indexed** array of strings `details`. Each element of `details` provides information about a given passenger compressed into a string of length `15`. The system is such that: |
| 10 | + |
| 11 | + |
| 12 | + |
| 13 | +- The first ten characters consist of the phone number of passengers. |
| 14 | + |
| 15 | +- The next character denotes the gender of the person. |
| 16 | + |
| 17 | +- The following two characters are used to indicate the age of the person. |
| 18 | + |
| 19 | +- The last two characters determine the seat allotted to that person. |
| 20 | + |
| 21 | + |
| 22 | +Return **the number of passengers who are **strictly ****more than 60 years old**.** |
| 23 | + |
| 24 | + |
| 25 | +Example 1: |
| 26 | + |
| 27 | +``` |
| 28 | +Input: details = ["7868190130M7522","5303914400F9211","9273338290F4010"] |
| 29 | +Output: 2 |
| 30 | +Explanation: The passengers at indices 0, 1, and 2 have ages 75, 92, and 40. Thus, there are 2 people who are over 60 years old. |
| 31 | +``` |
| 32 | + |
| 33 | +Example 2: |
| 34 | + |
| 35 | +``` |
| 36 | +Input: details = ["1313579440F2036","2921522980M5644"] |
| 37 | +Output: 0 |
| 38 | +Explanation: None of the passengers are older than 60. |
| 39 | +``` |
| 40 | + |
| 41 | + |
| 42 | +**Constraints:** |
| 43 | + |
| 44 | + |
| 45 | + |
| 46 | +- `1 <= details.length <= 100` |
| 47 | + |
| 48 | +- `details[i].length == 15` |
| 49 | + |
| 50 | +- `details[i] consists of digits from '0' to '9'.` |
| 51 | + |
| 52 | +- `details[i][10] is either 'M' or 'F' or 'O'.` |
| 53 | + |
| 54 | +- The phone numbers and seat numbers of the passengers are distinct. |
| 55 | + |
| 56 | + |
| 57 | + |
| 58 | +## Solution |
| 59 | + |
| 60 | +```javascript |
| 61 | +/** |
| 62 | + * @param {string[]} details |
| 63 | + * @return {number} |
| 64 | + */ |
| 65 | +var countSeniors = function(details) { |
| 66 | + var count = 0; |
| 67 | + for (var i = 0; i < details.length; i++) { |
| 68 | + if (details[i][11] > '6' || (details[i][11] === '6' && details[i][12] > '0')) { |
| 69 | + count += 1; |
| 70 | + } |
| 71 | + } |
| 72 | + return count; |
| 73 | +}; |
| 74 | +``` |
| 75 | + |
| 76 | +**Explain:** |
| 77 | + |
| 78 | +nope. |
| 79 | + |
| 80 | +**Complexity:** |
| 81 | + |
| 82 | +* Time complexity : O(n). |
| 83 | +* Space complexity : O(1). |
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