[Leetcode] 896. Monotonic Array

Problems: https://leetcode.com/problems/monotonic-array/

Solution1:
添加新方法判断

class Solution {
    public boolean isMonotonic(int[] A) {
        return isIncreasing(A) || isDecreasing(A);
    }
    
    public boolean isIncreasing(int[] A) {
        for(int i = 0; i < A.length-1; i++) {
            if((A[i+1] - A[i]) < 0) {
                return false;
            }
        }
        return true;
    }
    
    public boolean isDecreasing(int[] A) {
        for(int i = 0; i < A.length-1; i++) {
            if((A[i+1] - A[i]) > 0) {
                return false;
            }
        }
        return true;
    }
}

Solution2
One pass

class Solution {
    public boolean isMonotonic(int[] A) {
        boolean increasing = true;
        boolean decreasing = true;
        for(int i = 0; i < A.length-1; i++) {
            if ((A[i+1] - A[i]) > 0) {
                decreasing = false;
            }
            if ((A[i+1] - A[i]) < 0) {
                increasing = false;
            }
        }
        return increasing || decreasing;
    }
}