reformat code

This commit is contained in:
shellhub 2020-09-17 15:19:53 +08:00
parent 2ecef7e44a
commit 47ad7ec9b3
2 changed files with 50 additions and 75 deletions

50
Others/TwoPointers.java Normal file
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@ -0,0 +1,50 @@
package Others;
import java.util.Arrays;
/**
* The two pointer technique is a useful tool to utilize when searching for pairs in a sorted array.
* <p>
* link: https://www.geeksforgeeks.org/two-pointers-technique/
*/
class TwoPointers {
public static void main(String[] args) {
int[] arr = {10, 20, 35, 50, 75, 80};
int key = 70;
assert isPairedSum(arr, key); /* 20 + 60 == 70 */
arr = new int[]{1, 2, 3, 4, 5, 6, 7};
key = 13;
assert isPairedSum(arr, key); /* 6 + 7 == 13 */
key = 14;
assert !isPairedSum(arr, key);
}
/**
* Given a sorted array arr (sorted in ascending order).
* Find if there exists any pair of elements such that their sum is equal to key.
*
* @param arr the array contains elements
* @param key the number to search
* @return {@code true} if there exists a pair of elements, {@code false} otherwise.
*/
private static boolean isPairedSum(int[] arr, int key) {
/* array sorting is necessary for this algorithm to function correctly */
Arrays.sort(arr);
int i = 0; /* index of first element */
int j = arr.length - 1; /* index of last element */
while (i < j) {
if (arr[i] + arr[j] == key) {
return true;
} else if (arr[i] + arr[j] < key) {
i++;
} else {
j--;
}
}
return false;
}
}

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import java.util.*;
import java.lang.*;
import java.io.*;
//https://www.geeksforgeeks.org/two-pointers-technique/
class TwoPointersAlgo {
//This function prints all pairs in the array that sum to a number X. If no such pair exists then output will be -1.
static void twoSum(int A[], int X)
{
Arrays.sort(A);
//Array sorting is necessary for this algo to function correctly
int n = A.length;
int i = 0, j = n-1, flag=0;
//Implementation of the algorithm starts
while(i<j)
{
if(A[i]+A[j]==X)
{
System.out.println(A[i] + " " + A[j] + " " + X);
flag = 1;
i++;
j--;
}
else if(A[i]+A[j]<X)
{
i++;
}
else j--;
}
//Implementation ends
if(flag==0)
System.out.println(-1);
}//end of function twoSum
public static void main (String[] args) {
Scanner in = new Scanner(System.in);
int t,n;
t = in.nextInt();
//for number of test cases
while(t>0)
{
t--;
n = in.nextInt();
int a[] = new int[n];
for(int i = 0; i<n; i++)
{
a[i] = in.nextInt();
}
//taking array input
int k = in.nextInt(); //the total of the pair entered by the user
twoSum(a, k);
}
}//end of main
}//end of class
/*Sample Input/Output
Input:
2
7
1 2 3 4 5 6 7
98
7
1 2 3 4 5 6 7
8
Output:
-1
1 7 8
2 6 8
3 5 8
*/