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topic
896. Monotonic sequence
If the array is monotonically increasing or monotonically decreasing, then it is monotonous.
If for all i <= j, A[i] <= A[j], then the array A is monotonically increasing. If for all i <= j, A[i]> = A[j], then the array A is monotonically decreasing.
It returns true when the given array A is a monotonic array, otherwise it returns false.
Example 1:
输入：[1,2,2,3]
输出：true
Example 2:
输入：[6,5,4,4]
输出：true
Example 3:
输入：[1,3,2]
输出：false
Example 4:
输入：[1,2,4,5]
输出：true
Example 5:
输入：[1,1,1]
输出：true
prompt:
1 <= A.length <= 50000
-100000 <= A[i] <= 100000
Problem solution (Java)
class Solution
{
public boolean isMonotonic(int[] A)
{
//如果A数组的长度为1
if(A.length == 1)
{
return true;
}
//当数组的长度大于1时
//遍历A数组
//记录递增的数量
int upCount = 0;
//记录递减的数量
int downCount = 0;
for(int index = 1;index < A.length;index++)
{
if(A[index] >= A[index - 1])
{
upCount++;
}
if(A[index] <= A[index - 1])
{
downCount++;
}
}
//只要为递增或递减数组均可
return (upCount == A.length - 1 || downCount == A.length - 1);
}
}