Description
Given an integer array nums, return true if there exists a triple of indices (i, j, k) such that i < j < k and nums[i] < nums[j] < nums[k]. If no such indices exists, return false.
Example 1:
Input: nums = [1,2,3,4,5]
Output: true
Explanation: Any triplet where i < j < k is valid.
Example 2:
Input: nums = [5,4,3,2,1]
Output: false
Explanation: No triplet exists.
Example 3:
Input: nums = [2,1,5,0,4,6]
Output: true
Explanation: One of the valid triplet is (1, 4, 5), because nums[1] == 1 < nums[4] == 4 < nums[5] == 6.
Constraints:
1 <= nums.length <= 5 * 105-231 <= nums[i] <= 231 - 1
Follow up: Could you implement a solution that runs in
O(n) time complexity and
O(1) space complexity?
Solutions
Solution 1
PythonJavaC++GoTypeScriptRust
class Solution:
def increasingTriplet(self, nums: List[int]) -> bool:
mi, mid = inf, inf
for num in nums:
if num > mid:
return True
if num <= mi:
mi = num
else:
mid = num
return False(code-box)
class Solution {
public boolean increasingTriplet(int[] nums) {
int min = Integer.MAX_VALUE, mid = Integer.MAX_VALUE;
for (int num : nums) {
if (num > mid) {
return true;
}
if (num <= min) {
min = num;
} else {
mid = num;
}
}
return false;
}
}(code-box)
class Solution {
public:
bool increasingTriplet(vector<int>& nums) {
int mi = INT_MAX, mid = INT_MAX;
for (int num : nums) {
if (num > mid) return true;
if (num <= mi)
mi = num;
else
mid = num;
}
return false;
}
};(code-box)
func increasingTriplet(nums []int) bool {
min, mid := math.MaxInt32, math.MaxInt32
for _, num := range nums {
if num > mid {
return true
}
if num <= min {
min = num
} else {
mid = num
}
}
return false
}(code-box)
function increasingTriplet(nums: number[]): boolean {
let n = nums.length;
if (n < 3) return false;
let min = nums[0],
mid = Number.MAX_SAFE_INTEGER;
for (let num of nums) {
if (num <= min) {
min = num;
} else if (num <= mid) {
mid = num;
} else if (num > mid) {
return true;
}
}
return false;
}(code-box)
impl Solution {
pub fn increasing_triplet(nums: Vec<i32>) -> bool {
let n = nums.len();
if n < 3 {
return false;
}
let mut min = i32::MAX;
let mut mid = i32::MAX;
for num in nums.into_iter() {
if num <= min {
min = num;
} else if num <= mid {
mid = num;
} else {
return true;
}
}
false
}
}(code-box)
