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### by Sumit Chourasia | Sep 27, 2020 | Category :coding | Tags : algorithmarrayडेटा-संरचनाआसानleetcode

#### Valid Mountain Array - Array - Easy - LeetCode - मिनी टीवी

Given an array A of integers, return true if and only if it is a valid mountain array.

Recall that A is a mountain array if and only if:

A.length >= 3
There exists some i with 0 < i < A.length - 1 such that:
A[0] < A[1] < ... A[i-1] < A[i]
A[i] > A[i+1] > ... > A[A.length - 1]

Example 1:

Input: [2,1]
Output: false
Example 2:

Input: [3,5,5]
Output: false
Example 3:

Input: [0,3,2,1]
Output: true

Note:

0 <= A.length <= 10000
0 <= A[i] <= 10000

``````public class Solution {
public bool ValidMountainArray(int[] A) {
if(A.Length<3){
return false;
}

if(A[0]>A[1]){
return false;
}

bool isIncreasing = true;
for(int i=1;i<A.Length;i++){
if(isIncreasing){
if(A[i-1]>A[i]){
isIncreasing=false;
}
}
else{
if(A[i-1]<=A[i]){
return false;
}
}
}

//check if we found decreasing curve or not
return isIncreasing==false;
}
}``````

Time Complexity: O(n)

Space Complexity: O(1)

Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia