Leetcode448.java

packagecom.company;

importjava.util.ArrayList;
importjava.util.List;

publicclassLeetcode448 {
publicstaticvoidmain(String[] args) {
int[] arr={4,3,2,7,8,2,3,1};
// List<Integer> ans=new ArrayList<>();
List<Integer> ans=disappear(arr);
System.out.println(ans);
 }

staticList<Integer> disappear(int[] arr) {
inti = 0;
while (i < arr.length) {
intcorrectIndex = arr[i] - 1;
if (arr[i] != arr[correctIndex]) {
swap(arr, i, correctIndex);
 } else {
i++;
 }
 }

List<Integer> ans = newArrayList<>();
for (intj = 0; j < arr.length; j++) {
if (arr[j] != j + 1)
 { ans.add(j+1);
 }
 }
returnans;
 }

staticvoidswap(int[] arr, inta, intb){
inttemp=arr[a];
arr[a]=arr[b];
arr[b]=temp;
 }
}