Monotonic Array
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.
判斷一個數組是否有序,降序升序都可以。
思路:給一個標記來記當前的陣列排序方法,如果排序方法改變了,那麼就不是有序的陣列
public boolean isMonotonic(int[] A) { int f=0; for (int i = 0; i < A.length-1; i++) { if(A[i]==A[i+1]){ continue; }else if(A[i]<A[i+1]){ if( f == 0){ f = 1; }else if(f==2){ return false; } }else if(A[i]>A[i+1]){ if( f == 0){ f = 2; }else if(f==1){ return false; } } } return true; }