Merge pull request #1 from ishikasinha-d/sum-of-three-values

Add sum_of_three values in cpp

Author: ishikasinha-d

Arrays/sum_of_three_values.c++

@@ -0,0 +1,57 @@
+// Given an array of size n. Your task is to find three values (at distinct positions) whose sum is x. 
+// (1<=n<=5000, 1<=x<=10^9)
+
+// Input:
+// 4 8
+// 2 7 5 1
+
+// Output:
+// 1 3 4
+
+// Time complexity: O(n^2)
+// Concepts Involved: Sorting, Pointers
+
+#include<bits/stdc++.h>
+#define fl(i,a,b) for(i=a;i<b;i++)
+#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
+using namespace std;
+typedef long long int ll;
+ 
+int main()
+{ 
+   fast;
+ 
+ll n,k, target, l, r; cin>>n>>k; 
+vector<pair<ll,ll>> a;
+pair<ll, ll > p;
+
+for(ll i=0; i<n; i++)
+{
+    cin>>p.first;
+    p.second=i+1;
+    a.push_back(p);
+} 
+sort(begin(a), end(a));
+
+for (ll i = 0; i < n; i++)
+{
+    l=0;
+    r=n-1;
+    target= k-a[i].first;
+    while(l<r)
+    {
+        if(a[l].first+a[r].first==target && i!=l && l!=r && r!=i)
+            {
+                cout<<a[l].second<<" "<<a[r].second<<" "<<a[i].second;
+                return 0;
+            }
+        else if(a[l].first+a[r].first<=target)
+            l++;
+        else
+            r--;
+    }
+    
+}
+    cout<<"IMPOSSIBLE";
+    return 0;
+}