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Add tests for TwoSumProblem and reduce duplication (fixes #4177) (#4176)

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Rutikpatil0123
2023-05-02 22:33:21 +05:30
committed by GitHub
parent fb18c27905
commit bb830e9559
3 changed files with 45 additions and 125 deletions
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109
src/main/java/com/thealgorithms/misc/TwoSumProblem.java
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@ -1,109 +0,0 @@
package com.thealgorithms.misc;
import java.util.*;
import java.util.stream.Collectors;
public class TwoSumProblem {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.print("Enter the target sum ");
int ts = scan.nextInt();
System.out.print("Enter the number of elements in the array ");
int n = scan.nextInt();
System.out.println("Enter all your array elements:");
int[] arr = new int[n];
for (int i = 0; i < n; i++) {
arr[i] = scan.nextInt();
}
TwoSumProblem t = new TwoSumProblem();
System.out.println(
"Brute Force Approach\n" +
Arrays.toString(t.BruteForce(arr, ts)) +
"\n"
);
System.out.println(
"Two Pointer Approach\n" +
Arrays.toString(t.TwoPointer(arr, ts)) +
"\n"
);
System.out.println(
"Hashmap Approach\n" + Arrays.toString(t.HashMap(arr, ts))
);
}
public int[] BruteForce(int[] nums, int target) {
//Brute Force Approach
int[] ans = new int[2];
for (int i = 0; i < nums.length; i++) {
for (int j = i + 1; j < nums.length; j++) {
if (nums[i] + nums[j] == target) {
ans[0] = i;
ans[1] = j;
break;
}
}
}
return ans;
}
public int[] TwoPointer(int[] nums, int target) {
// HashMap Approach
int[] ans = new int[2];
HashMap<Integer, Integer> hm = new HashMap<Integer, Integer>();
for (int i = 0; i < nums.length; i++) {
hm.put(i, nums[i]);
}
HashMap<Integer, Integer> temp = hm
.entrySet()
.stream()
.sorted((i1, i2) -> i1.getValue().compareTo(i2.getValue()))
.collect(
Collectors.toMap(
Map.Entry::getKey,
Map.Entry::getValue,
(e1, e2) -> e1,
LinkedHashMap::new
)
);
int start = 0;
int end = nums.length - 1;
while (start < end) {
int currSum = (Integer) temp.values().toArray()[start] +
(Integer) temp.values().toArray()[end];
if (currSum == target) {
ans[0] = (Integer) temp.keySet().toArray()[start];
ans[1] = (Integer) temp.keySet().toArray()[end];
break;
} else if (currSum > target) {
end -= 1;
} else if (currSum < target) {
start += 1;
}
}
return ans;
}
public int[] HashMap(int[] nums, int target) {
//Using Hashmaps
int[] ans = new int[2];
HashMap<Integer, Integer> hm = new HashMap<Integer, Integer>();
for (int i = 0; i < nums.length; i++) {
hm.put(nums[i], i);
}
for (int i = 0; i < nums.length; i++) {
int t = target - nums[i];
if (hm.containsKey(t) && hm.get(t) != i) {
ans[0] = i;
ans[1] = hm.get(t);
break;
}
}
return ans;
}
}