3637. Trionic Array I

/**
 * Problem: LeetCode 3637 - Trionic Array I
 * Difficulty: Easy
 * Language: Java
 * Author: CodeByTushu
 */
class Solution {
    public boolean isTrionic(int[] nums) {
        int n = nums.length;
        if (n < 4) {
            return false;
        }

        int i = 0;

        // Phase 1: Strictly increasing to peak p
        while (i + 1 < n && nums[i] < nums[i + 1]) {
            i++;
        }
        int p = i;
        if (p == 0 || p >= n - 2) {
            return false;
        }

        // Phase 2: Strictly decreasing to valley q
        while (i + 1 < n && nums[i] > nums[i + 1]) {
            i++;
        }
        int q = i;
        if (q == p || q >= n - 1) {
            return false;
        }

        // Phase 3: Strictly increasing to the end
        while (i + 1 < n && nums[i] < nums[i + 1]) {
            i++;
        }

        return i == n - 1;
    }
}

"""
Problem: LeetCode 3637 - Trionic Array I
Difficulty: Easy
Language: Python
Author: CodeByTushu
"""
from typing import List


class Solution:
    def isTrionic(self, nums: List[int]) -> bool:
        n = len(nums)
        if n < 4:
            return False

        i = 0

        # Phase 1: Strictly increasing to peak p
        while i + 1 < n and nums[i] < nums[i + 1]:
            i += 1
        p = i
        if p == 0 or p >= n - 2:
            return False

        # Phase 2: Strictly decreasing to valley q
        while i + 1 < n and nums[i] > nums[i + 1]:
            i += 1
        q = i
        if q == p or q >= n - 1:
            return False

        # Phase 3: Strictly increasing to the end
        while i + 1 < n and nums[i] < nums[i + 1]:
            i += 1

        return i == n - 1

/**
 * Problem: LeetCode 3637 - Trionic Array I
 * Difficulty: Easy
 * Language: C++
 * Author: CodeByTushu
 */
#include <vector>

using namespace std;

class Solution {
public:
    bool isTrionic(vector<int>& nums) {
        int n = nums.size();
        if (n < 4) {
            return false;
        }

        int i = 0;

        // Phase 1: Strictly increasing to peak p
        while (i + 1 < n && nums[i] < nums[i + 1]) {
            i++;
        }
        int p = i;
        if (p == 0 || p >= n - 2) {
            return false;
        }

        // Phase 2: Strictly decreasing to valley q
        while (i + 1 < n && nums[i] > nums[i + 1]) {
            i++;
        }
        int q = i;
        if (q == p || q >= n - 1) {
            return false;
        }

        // Phase 3: Strictly increasing to the end
        while (i + 1 < n && nums[i] < nums[i + 1]) {
            i++;
        }

        return i == n - 1;
    }
};

/**
 * Problem: LeetCode 3637 - Trionic Array I
 * Difficulty: Easy
 * Language: JavaScript
 * Author: CodeByTushu
 */
/**
 * @param {number[]} nums
 * @return {boolean}
 */
var isTrionic = function(nums) {
    const n = nums.length;
    if (n < 4) {
        return false;
    }

    let i = 0;

    // Phase 1: Strictly increasing to peak p
    while (i + 1 < n && nums[i] < nums[i + 1]) {
        i++;
    }
    const p = i;
    if (p === 0 || p >= n - 2) {
        return false;
    }

    // Phase 2: Strictly decreasing to valley q
    while (i + 1 < n && nums[i] > nums[i + 1]) {
        i++;
    }
    const q = i;
    if (q === p || q >= n - 1) {
        return false;
    }

    // Phase 3: Strictly increasing to the end
    while (i + 1 < n && nums[i] < nums[i + 1]) {
        i++;
    }

    return i === n - 1;
};