Added left and right index of an element problem

GFG/left-right-index.cpp

@@ -0,0 +1,96 @@
+// Question link - https://practice.geeksforgeeks.org/problems/find-first-and-last-occurrence-of-x0849/1
+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+ // } Driver Code Ends
+class Solution
+{
+    public:
+
+    long s1(vector<long long> v, long long x)
+    {
+        long i=0,j=v.size();
+        while(i<=j)
+        {
+            long mid=(i+j)/2;
+            if(v[mid]==x)
+            {
+                if(mid==0)
+                 return 0;
+                else if(v[mid-1]!=x)
+                  return mid;
+                else
+                  j=mid-1; 
+            }
+            else if(v[mid]>x)
+             j=mid-1;
+            else 
+             i=mid+1;
+        }
+         return -1;
+    }
+
+    long s2(vector<long long> v, long long x)
+    {
+        long i=0,j=v.size();
+        while(i<=j)
+        {
+            long mid=(i+j)/2;
+            if(v[mid]==x)
+            {
+                if(mid==v.size()-1)
+                 return v.size()-1;
+                else if(v[mid+1]!=x)
+                  return mid;
+                else
+                  i=mid+1; 
+            }
+            else if(v[mid]>x)
+             j=mid-1;
+            else 
+             i=mid+1;
+        }
+         return -1;
+    }
+
+    pair<long,long> indexes(vector<long long> v, long long x)
+    {
+        pair <long,long> ans;
+        ans.first=s1(v,x);
+        ans.second=s2(v,x);
+        return ans;
+    }
+};
+
+// { Driver Code Starts.
+
+int main()
+ {
+    long long t;
+    cin>>t;
+    while(t--)
+    {
+        long long n, k;
+        vector<long long>v;
+        cin>>n;
+        for(long long i=0;i<n;i++)
+        {
+            cin>>k;
+            v.push_back(k);
+        }
+        long long x;
+        cin>>x;
+        Solution obj;
+        pair<long,long> pair = obj.indexes(v, x);
+
+        if(pair.first==pair.second and pair.first==-1)
+        cout<< -1 <<endl;
+        else
+        cout<<pair.first<<" "<<pair.second<<endl;
+
+    }
+	return 0;
+}
+  // } Driver Code Ends