932. Monotonic Array
Difficulty: Easy
Topics: Array
Similar Questions:
Problem:
An array is monotonic if it is either monotone increasing or monotone decreasing.
An array A is monotone increasing if for all i <= j, A[i] <= A[j]. An array A is monotone decreasing if for all i <= j, A[i] >= A[j].
Return true if and only if the given array A is monotonic.
Example 1:
Input: [1,2,2,3] Output: true
Example 2:
Input: [6,5,4,4] Output: true
Example 3:
Input: [1,3,2] Output: false
Example 4:
Input: [1,2,4,5] Output: true
Example 5:
Input: [1,1,1] Output: true
Note:
1 <= A.length <= 50000-100000 <= A[i] <= 100000
Solutions:
class Solution {
public:
bool isMonotonic(vector<int>& A) {
if (A.size() <= 2) return true;
int cmp = 0;
for (int i = 1; i < A.size(); ++i) {
if (A[i] == A[i-1]) continue;
if (A[i] > A[i-1]) {
if (cmp == -1) return false;
cmp = 1;
} else {
if (cmp == 1) return false;
cmp = -1;
}
}
return true;
}
};