Added my successful submissions as well.

Introductory Problems/Chessboard and Queens (1624)/anubhav.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+int column[8]={0}, d1[15]={0},d2[15]={0};
+char c[8][8];
+using namespace std;
+int ans;
+void rec(int q)
+{
+    if(!(q-8))
+        ans++;
+    else{
+        for(int i=0;i<8;i++)
+        {
+            if(!( column[i] or d1[q+ i] or d2[7-q+i]) and c[q][i]=='.')
+            {
+                column[i] = d1[q+ i] = d2[7-q+i]=1;
+                rec(q+1);
+                column[i] = d1[q+ i] = d2[7-q+i]=0;
+            }
+        }
+    }
+     return;
+}
+int main() {
+	for(int i=0;i<8;i++)
+	for(int j=0;j<8;j++)
+	    cin>>c[i][j];
+	rec(0);
+    cout<<ans;
+	return 0;
+}

Introductory Problems/Palindrome Reorder (1755)/anubhav.py

@@ -0,0 +1,9 @@
+s,a,o,c,l=input(),'','',0,[0]*27
+for i in s:
+    l[ord(i)-ord('A')+1]+=1
+for i in range(1,27):
+    a+=chr(i+ord('A')-1)*(l[i]//2)
+    if l[i]%2==1:o,c=chr(i+65-1),c+1
+    if(c>1):break
+if c>1:print("NO SOLUTION")
+else:print(a+o+a[::-1])

Sorting and Searching/Maximum Subarray Sum (1643)/anubhav.cpp

@@ -0,0 +1,36 @@
+#include <bits/stdc++.h>
+#define loop(i,n) for(long long i=0;i<n;++i)
+using namespace std;
+int main()
+{
+    long long n;
+    scanf("%lld",&n);
+    long long a[n];
+    bool pos=0;
+    loop(i,n)
+    {
+        scanf("%lld",a+i);
+        if(a[i]>0)
+            pos=1;
+    }
+    long long max_end=0, max_so_far=0;
+    if(pos)
+    {
+        loop(i,n)
+        {
+            max_end+=a[i];
+            if(max_end<0)
+                max_end=0;
+            if(max_so_far<max_end)
+                max_so_far=max_end;
+        }
+    }
+    else{
+        max_so_far=-1000000000;
+        loop(i,n)
+        if(max_so_far<a[i])
+        max_so_far=a[i];
+    }
+    printf("%lld",max_so_far);
+    return 0;
+}

Sorting and Searching/Playlist (1141)/anubhav.cpp

@@ -0,0 +1,24 @@
+#include <bits/stdc++.h>
+#define loop(i,n) for(int i=0;i<n;++i)
+using namespace std;
+int main()
+{
+    int n,len=0;
+    scanf("%d",&n);
+    int a[n];
+    map <int, int > song;
+    loop(i,n)
+    {
+        scanf("%d",a+i);
+        song[ a[i] ]=0;
+    }
+    int j=0,i=0;
+    loop(i,n)
+    {
+        j=max(j,song[a[i]]);
+        len=max(len,i-j+1);
+        song[a[i]]=i+1;
+    }
+    printf("%d",len);
+    return 0;
+}

Sorting and Searching/Room Allocation (1164)/anubhav.cpp

@@ -0,0 +1,44 @@
+#include <bits/stdc++.h>
+#define loop(i,n) for(int i=0;i<n;++i)
+using namespace std;
+int main()
+{
+    int n,a,d;
+    scanf("%d",&n);
+    multiset <pair < int , int > >arrival;
+    multiset < pair < int, int > >depart;
+    vector < pair < int, int > > sch;
+    map<int, int > room;
+    multiset < pair < int, int > >::iterator itr;
+    loop(i,n)
+    {
+        scanf("%d %d",&a,&d);
+        sch.push_back(make_pair(a,d));
+        arrival.insert(make_pair(a,i));
+        depart.insert(make_pair(d,i));
+    }
+    int room_num=0;
+    while(arrival.size())
+    {
+        ++room_num;
+        int arr,ind,dept;
+        itr=arrival.begin();
+        while(true)
+        {
+            arr=(*itr).first;
+            ind=(*itr).second;
+
+            arrival.erase(itr);
+
+            room[ind]=room_num;
+            dept=sch[ind].second;
+            depart.erase(depart.find(make_pair(dept,ind)));
+
+            itr=arrival.upper_bound(make_pair(dept,10000000));
+            if(itr==arrival.end())
+                break;
+        }
+    }
+    cout<<room_num<<endl;
+    loop(i, sch.size() )
+        cout<<room[i]<<' ';