1 2
1 3
3 2
3 4
4 5
6 7
7 8

1 in = 0 out = 2
2 in = 2 out = 0
3 in = 1 out = 2
4 in = 1 out = 1
5 in = 1 out = 0
6 in = 0 out = 1
7 in = 1 out = 1
8 in = 1 out = 0

import java.lang.reflect.Array;
public class Main {
public static void main(String[] args) {
int[][] array = {
{1, 2},
{1, 3},
{3, 2},
{3, 4},
{4, 5},
{6, 7},
{7, 8}
};


int max = array[0][0];
for(int i = 0; i<array[0].length; i++){
for(int j = 0; j<array.length; j++){
if(max <array[j][i]) {
max = array[j][i];
}
}
}

final int values = max;


int[] input = new int[values];
for (int i = 0; i < input.length; i++) {
input[i] = 0;
}


int[] output = new int[values];
for (int i = 0; i < output.length; i++) {
output[i] = 0;
}

for (int i = 0; i < array.length; i++) {
for (int k = 1; k <= values; k++) {
if (array[i][0] == k) {
output[k - 1] += 1;
}
if (array[i][1] == k) {
input[k - 1] += 1;
}
}
}

for(int k=0; k<values; k++) {
System.out.println(k+1 + " in = " + input[k] + " out = " + output[k]);
}
}
}