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
function solution(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].
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
const N = A.length;
const map = {};
for (let i = 0; i < N; i++) {
if (map[A[i]]) {
map[A[i]]++;
} else {
map[A[i]] = 1;
}
}
let maxCount = 0;
let candidate = undefined;
for (const [value, count] of Object.entries(map)) {
if (count > maxCount) {
maxCount = count;
candidate = parseInt(value);
}
}
if (maxCount >= (N / 2) + 1) {
for (let i = 0; i < N; i++) {
if (A[i] === candidate) {
return i;
}
}
}
return -1;
}
[1, 2, 1]
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
const N = A.length;
const map = {};
for (let i = 0; i < N; i++) {
if (map[A[i]]) {
map[A[i]]++;
} else {
map[A[i]] = 1;
}
}
let maxCount = 0;
let candidate = undefined;
for (const [value, count] of Object.entries(map)) {
if (count > maxCount) {
maxCount = count;
candidate = parseInt(value);
}
}
console.log(maxCount);
console.log(candidate)
if (maxCount >= (N / 2) + 1) {
for (let i = 0; i < N; i++) {
if (A[i] === candidate) {
return i;
}
}
}
return -1;
}
[1, 2, 1]
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
const N = A.length;
const map = {};
for (let i = 0; i < N; i++) {
if (map[A[i]]) {
map[A[i]]++;
} else {
map[A[i]] = 1;
}
}
let maxCount = 0;
let candidate = undefined;
for (const [value, count] of Object.entries(map)) {
if (count > maxCount) {
maxCount = count;
candidate = parseInt(value);
}
}
console.log(maxCount);
console.log(candidate)
if (maxCount >= Mat(N / 2) + 1) {
for (let i = 0; i < N; i++) {
if (A[i] === candidate) {
return i;
}
}
}
return -1;
}
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
const N = A.length;
const map = {};
for (let i = 0; i < N; i++) {
if (map[A[i]]) {
map[A[i]]++;
} else {
map[A[i]] = 1;
}
}
let maxCount = 0;
let candidate = undefined;
for (const [value, count] of Object.entries(map)) {
if (count > maxCount) {
maxCount = count;
candidate = parseInt(value);
}
}
console.log(maxCount);
console.log(candidate)
if (maxCount >= Math.floor(N / 2) + 1) {
for (let i = 0; i < N; i++) {
if (A[i] === candidate) {
return i;
}
}
}
return -1;
}
[1, 2, 1]
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
const N = A.length;
const map = {};
for (let i = 0; i < N; i++) {
if (map[A[i]]) {
map[A[i]]++;
} else {
map[A[i]] = 1;
}
}
let maxCount = 0;
let candidate = undefined;
for (const [value, count] of Object.entries(map)) {
if (count > maxCount) {
maxCount = count;
candidate = parseInt(value);
}
}
if (maxCount >= Math.floor(N / 2) + 1) {
for (let i = 0; i < N; i++) {
if (A[i] === candidate) {
return i;
}
}
}
return -1;
}
[1, 2, 1]
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
const N = A.length;
const map = {};
for (let i = 0; i < N; i++) {
if (map[A[i]]) {
map[A[i]]++;
} else {
map[A[i]] = 1;
}
}
let maxCount = 0;
let candidate = undefined;
for (const [value, count] of Object.entries(map)) {
if (count > maxCount) {
maxCount = count;
candidate = parseInt(value);
}
}
if (maxCount >= Math.floor(N / 2) + 1) {
for (let i = 0; i < N; i++) {
if (A[i] === candidate) {
return i;
}
}
}
return -1;
}
The solution obtained perfect score.