Added solution

Author: avidLearnerInProgress

amazon/almost_sorted_sequence.cpp

@@ -0,0 +1,66 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+int mod=1e9+7;
+#define F(a,b,var) for(int var=a;var<b;var++)
+#define FAST_INP  ios_base::sync_with_stdio(false);cin.tie(NULL)
+
+void almost_sorted(vector<int> &sequence){
+    //edgecases
+    if(sequence.size() < 2){
+        cout<<"Yes\n"; //since less than 2 means it can be reversed as well as swapped
+        return;
+    }
+    
+    if(is_sorted(sequence.begin(), sequence.end())){
+        cout<<"Yes\n"; //already sorted
+        return;
+    }
+        
+    //vector is partially sorted..
+    int N = sequence.size();
+    int i = 0, j = sequence.size() - 1;
+    
+    while(i != N && sequence[i+1] > sequence[i])
+        i++; //find start of partial array where it breaks the sorted sequence
+    while(j >= 0 && sequence[j-1] < sequence[j])
+        j--; //find end of partial array where it breaks the sorted sequence 
+    
+    //start and end of unsorted - subarray
+    swap(sequence[i], sequence[j]);
+    if(is_sorted(sequence.begin(), sequence.end())){
+        cout<<"yes\n"; //partial is now sorted 
+        cout<<"swap "<<(i+1)<<" "<<(j+1)<<"\n";
+        return;
+    }
+
+    int k = i + 1, l = j - 1;
+    while(k < l){
+        swap(sequence[k], sequence[l]); //keep swapping the entire partial array .. basically reversing the array
+        k++, l--;
+    }
+    
+    if(is_sorted(sequence.begin(), sequence.end())){
+        cout<<"yes\n"; //partial is now sorted 
+        cout<<"reverse "<<(i+1)<<" "<<(j+1)<<"\n";
+        return;
+    }
+    else{
+        cout<<"no\n"; // it is not possible to make the array properly sorted..
+        return;
+    }
+}
+
+int main() {
+    //code
+    FAST_INP;
+    int n;
+    cin>>n;
+
+    vector<int> seq(n);
+    for(int i = 0; i < n; i++)
+        cin>>seq[i];
+    
+    almost_sorted(seq);
+    return 0;
+}