An array A consisting of N integers is given. The dominator of array A is the value that occurs in more than half of the elements of A.
For example, consider array A such that
A[0] = 3 A[1] = 4 A[2] = 3 A[3] = 2 A[4] = 3 A[5] = -1 A[6] = 3 A[7] = 3The dominator of A is 3 because it occurs in 5 out of 8 elements of A (namely in those with indices 0, 2, 4, 6 and 7) and 5 is more than a half of 8.
Write a function
class Solution { public int solution(int[] A); }
that, given an array A consisting of N integers, returns index of any element of array A in which the dominator of A occurs. The function should return −1 if array A does not have a dominator.
For example, given array A such that
A[0] = 3 A[1] = 4 A[2] = 3 A[3] = 2 A[4] = 3 A[5] = -1 A[6] = 3 A[7] = 3the function may return 0, 2, 4, 6 or 7, as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- each element of array A is an integer within the range [−2,147,483,648..2,147,483,647].
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
[-1, -2, -3, -4]
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
[-1, -2, -3, -4]
[-1, -1, -1, -1, -1, -1]
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
[-1, -2, 1, -4]
[-1, -1, -1, -1, -1, -1]
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
[-1, -2, 1, 1, 1, 1, 1, 1, -4]
[-1, -1, -1, -1, -1, -1]
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
[-1, -2, 1, 1, 1, 1, 1, 1, 1, 1, 1, -4]
[-1, -1, -1, -1, -1, -1]
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
[-1, -2, 1, 1, 1, 1, 1, 1, 1, 1, 1, -4]
[-1, -1, -1, -1, -1, -1]
import java.util.*;
class Solution {
public int solution(int[] A) {
int dominationCount = 1;
int elementValue=0;
int temp[] = new int[A.length];
if(A.length == 1){
return 0;
}
for(int i = 0 ; i < temp.length ; i++){
temp[i] = A[i];
}
Arrays.sort(A);
for(int i = 0 ; i < A.length-1 ; i++){
if(A[i] == A[i+1]){
dominationCount++;
} else {
dominationCount = 1;
}
if(dominationCount > A.length/2 ) {
elementValue = A[i];
}
}
for(int i = 0 ; i < temp.length ; i++){
if(temp[i] == elementValue){
return i;
}
}
return -1;
}
}
The following issues have been detected: wrong answers.
all different and all the same elements
got 0, but element is not a dominator, value 0 has only 1 occurences (n=50)