PROBLEM DESCRIPTION
Given an unsorted array Arr of size N. Find the subarray Arr[s...e] such that sorting this subarray makes the whole array sorted.
SOLUTION
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class Solve {
int[] printUnsorted(int[] arr, int n) {
// [SORTED][misplaced_UNSORTED_misplaced][SORTED]
// Let us first try to find the smallest element which is misplaced
// Since that element is misplaced, it must be smaller than one of the elements on its left
int small = 0;
int max = arr[0];
for(int i=0; i<n; i++){
if(arr[i] < max){
small = i;
}
max = Math.max(max, arr[i]);
}
// If small is already at its correct position, the array must already be sorted
if(small == 0)
return new int[]{0, 0};
// Let us now try to find the largest element which is misplaced
// Since that element is misplaced, it must be larger than one of the elements on its right
int large = n-1;
int min = arr[n-1];
for(int i=n-1; i>=0; i--){
if(arr[i] > min){
large = i;
}
min = Math.min(min, arr[i]);
}
// the larger element will be on left side, in the unsorted form
return new int[]{large, small};
}
}