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Copy pathTwoNumberSum.java
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85 lines (71 loc) · 2.08 KB
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package com.java.sks.array;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
/**
* @author - Sandeep Singh
*/
public class TwoNumberSum {
/**
* @param array
* @param targetSum
* @return
* Time complexity o(n^2)
*/
public static int[] twoNumberSumON2(int[] array, int targetSum) {
for (int i = 0; i < array.length - 1; i++) {
for (int j = i + 1; j < array.length; j++) {
if (array[i] + array[j] == targetSum) {
return new int[]{array[i], array[j]};
}
}
}
return new int[0];
}
/**
* @param array
* @param targetSum
* @return
* Time complexity o(n) and Space Complexity O(n)
*/
static int[] twoNumberSumONON(int[] array, int targetSum) {
Map<Integer, Boolean> hashMap = new HashMap<>();
for (int localNumber : array) {
int potentialSum = targetSum - localNumber;
if (hashMap.containsKey(potentialSum)) {
return new int[]{potentialSum, localNumber};
}
hashMap.put(localNumber, true);
}
return new int[0];
}
/**
* @param array
* @param targetSum
* @return
* Time Complexity O(nLog(n)) Space complexity O(1)
*/
static int[] twoNumberSumNON(int[] array, int targetSum) {
Arrays.sort(array);
int left = 0;
int right = array.length - 1;
while (left < right) {
int currentSum = array[left] + array[right];
if (currentSum == targetSum) {
return new int[]{array[left], array[right]};
} else if (currentSum < targetSum) {
left++;
} else if (currentSum > targetSum) {
right--;
}
}
return new int[0];
}
public static void main(String[] args) {
int A[] = {1, 4, 45, 6, 10, -8};
int[] array = twoNumberSumNON(A, 16);
for (int i = 0; i < array.length; i++) {
System.out.println(array[i]);
}
}
}