Deloitte | COGNIZANT | IBM | CAPGEMINI
import java.util.*;
public class Main {
public static long solve(int n, int[] wealth) {
int maxWealth = 0;
for (int val : wealth) {
maxWealth = Math.max(maxWealth, val);
}
int maxPossibleSum = 2 * maxWealth;
Set<Long> uniquePowers= new HashSet<>();
long p = 1;
while (p <= maxPossibleSum) {
uniquePowers.add(p);
p *= 3;
}
Map<Integer, Integer> freq = new HashMap<>();
for (int w : wealth) {
freq.put(w, freq.getOrDefault(w, 0) + 1);
}
long count = 0;
for (int a : freq.keySet()) {
for (long x : uniquePowers) {
long b = x - a;
if (b < 0 || b > Integer.MAX_VALUE) continue;
if (freq.containsKey((int)b)) {
if (a < b) {
count += (long) freq.get(a) * freq.get((int)b);
} else if (a == b) {
count += (long) freq.get(a) * (freq.get(a) - 1) / 2;
}
}
}
}
return count;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int[] wealth = new int[n];
for (int i = 0; i < n; i++) {
wealth[i] = sc.nextInt();
}
System.out.println(solve(n, wealth));
}
}
valid pairs✅✅
#zl_technologies
1K ·