103 lines
2.7 KiB
C++
103 lines
2.7 KiB
C++
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//Description :c++ solution to find all the unique triplet without using any extra space.
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//using this method we will be able to find all the unique triplets
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//Time Complexity : O(n), where n is the array size
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//Space Complexity : O(1),it will take only constant amount of time.
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//sample
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// input 1: arr[]=[-1,0,1,2,-1,4]
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//output 1:[[-1,0,1][-1,-1,2]]
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//input 2:arr[]=[]
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//output 2:[]
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#include<bits/stdc++.h>
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using namespace std;
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void findTriplet(int arr[],int n,int sum) {
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int i;
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// Sort the input array
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sort(arr, arr + n);
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// For handling the cases when no such
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// triplets exits.
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bool flag = false;
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// Iterate over the array from start to n-2.
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for (i = 0; i < n - 2; i++)
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{
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if (i == 0 || arr[i] > arr[i - 1])
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{
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// Index of the first element in
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// remaining range.
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int start = i + 1;
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// Index of the last element
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int end = n - 1;
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// Setting our new target
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int target = sum - arr[i];
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while (start < end)
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{
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// Checking if current element
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// is same as previous
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if (start > i + 1
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&& arr[start] == arr[start - 1])
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{
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start++;
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continue;
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}
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// Checking if current element is
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// same as previous
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if (end < n - 1
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&& arr[end] == arr[end + 1])
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{
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end--;
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continue;
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}
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// If we found the triplets then print it
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// and set the flag
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if (target == arr[start] + arr[end])
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{
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cout << "[" << arr[i]
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<< "," << arr[start]
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<< "," << arr[end] << "] ";
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flag = true;
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start++;
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end--;
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}
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// If target is greater then
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// increment the start index
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else if (target > (arr[start] + arr[end]))
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{
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start++;
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}
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// If target is smaller than
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// decrement the end index
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else {
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end--;
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}
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}
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}
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}
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// If no such triplets found
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if (flag == false) {
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cout << "No Such Triplets Exist"
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<< "\n";
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}
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}
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int main()
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{
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// int arr[]={12,3,6,1,6,9};
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int arr[]={-1,0,1,2,-1,-4};
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int n=sizeof(arr)/sizeof(arr[0]);
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int sum=0;
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findTriplet(arr,n,sum);
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return 0;
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}
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