Added CSES solved problems

CSES/1_introductory_problems/10_trailing_zeros.cpp

@@ -0,0 +1,26 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+int solve()
+{
+    int n,ans=0;
+    cin>>n;
+    while(n>0)
+    {
+        ans+=n/=5;
+    }
+    return ans;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout<<solve()<<"\n";
+    return 0;
+}

CSES/1_introductory_problems/11_coin_piles.cpp

@@ -0,0 +1,32 @@
+#include<bits/stdc++.h>
+#define yes cout<<"YES"<<"\n"
+#define no cout<<"NO"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+bool solve()
+{
+    int a,b;
+    cin>>a>>b;
+    int t=2*(min(a,b))-max(a,b);
+    if(t<0||t%3)
+    {
+        return false;
+    }
+    return true;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    int t;
+    cin>>t;
+    while(t--)
+    {
+        solve()?yes:no;
+    }
+    return 0;
+}

CSES/1_introductory_problems/12_palindrome_number.cpp

@@ -0,0 +1,53 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+string solve()
+{
+    string s;
+    int n,odd_count=0;
+    vector<int>vec(26,0);
+    cin>>s;
+    n=s.size();
+    for(int i=0;i<n;i++)
+    {
+        vec[s[i]-'A']++;
+    }
+    for(int i=0;i<26;i++)
+    {
+        if(vec[i]&1)
+        {
+            odd_count++;
+            s[n/2]=(char)(i+'A');
+            vec[i]--;
+        }
+    }
+    if(odd_count>1)
+    {
+        return "NO SOLUTION";
+    }
+    int j=0;
+    for(int i=0;i<26;i++)
+    {
+        while(vec[i])
+        {
+            s[j]=(char)(i+'A');
+            s[n-j-1]=(char)(i+'A');;
+            vec[i]-=2;
+            j++;
+        }
+    }
+    return s;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout<<solve()<<"\n";
+    return 0;
+}

CSES/1_introductory_problems/13_gray_code.cpp

@@ -0,0 +1,37 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+void solve()
+{
+    int n,range,div,pos;
+    cin>>n;
+    range=pow(2,n);
+    string s(n,'0');
+    cout<<s<<"\n";
+    for(int i=1;i<range;i++)
+    {
+        div=1;
+        pos=n-1;
+        while(i%(div*2)==0)
+        {
+            div*=2;
+            pos--;
+        }            
+        s[pos]=(s[pos]=='0')?'1':'0';
+        cout<<s<<"\n";
+    }
+    return;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    solve();
+    return 0;
+}

CSES/1_introductory_problems/14_tower_of_hanoi.cpp

@@ -0,0 +1,30 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+void solve(int n,int a,int b,int c)
+{
+    if(n==1)
+    {
+        cout<<a<<" "<<c<<"\n";
+        return;
+    }
+    solve(n-1,a,c,b);
+    cout<<a<<" "<<c<<"\n";
+    solve(n-1,b,a,c);
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    int n;
+    cin>>n;
+    cout<<pow(2,n)-1<<"\n";
+    solve(n,1,2,3);
+    return 0;
+}

CSES/1_introductory_problems/1_weird_algorithm.cpp

@@ -0,0 +1,35 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+void solve()
+{
+    int n;
+    cin>>n;
+    while(n!=1)
+    {
+        cout<<n<<" ";
+        if(n&1)
+        {
+            n=n*3+1;
+        }
+        else
+        {
+            n/=2;
+        }
+    }
+    cout<<n;
+    return;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    solve();
+    return 0;
+}

CSES/1_introductory_problems/2_missing_number.cpp

@@ -0,0 +1,35 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+int solve()
+{
+    int n,temp;
+    cin>>n;
+    vector<bool>vec(n,false);
+    for(int i=0;i<n-1;i++)
+    {
+        cin>>temp;
+        vec[temp-1]=true;
+    }
+    for(int i=0;i<n;i++)
+    {
+        if(!vec[i])
+        {
+            return i+1;
+        }
+    }
+    return -1;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout<<solve()<<"\n";
+    return 0;
+}

CSES/1_introductory_problems/3_repetitions.cpp

@@ -0,0 +1,36 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+int solve()
+{
+    int n,curr,ans=0;
+    string s;
+    cin>>s;
+    n=s.size();
+    int i=0;
+    while(i<n)
+    {
+        curr=1;
+        while(i<n-1&&s[i]==s[i+1])
+        {
+            curr++;
+            i++;
+        }
+        i++;
+        ans=max(ans,curr);
+    }
+    return ans;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout<<solve();
+    return 0;
+}

CSES/1_introductory_problems/4_increasing_array.cpp

@@ -0,0 +1,35 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+int solve()
+{
+    int n,curr,prev,ans=0;
+    cin>>n;
+    cin>>prev;
+    for(int i=1;i<n;i++)
+    {
+        cin>>curr;
+        if(curr<prev)
+        {
+            ans+=prev-curr;
+        }
+        else
+        {
+            prev=curr;
+        }
+    }
+    return ans;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout<<solve();
+    return 0;
+}

CSES/1_introductory_problems/5_permutations.cpp

@@ -0,0 +1,40 @@
+#include<bits/stdc++.h>
+#define yes cout<<"Yes"<<"\n"
+#define no cout<<"No"<<"\n"
+#define endl "\n"
+#define int long long
+using ll=long long;
+using namespace std;
+
+void solve()
+{
+    int n;
+    cin>>n;
+    if(n==1)
+    {
+        cout<<1;
+        return;
+    }
+    if(n<=3)
+    {
+        cout<<"NO SOLUTION";
+        return;
+    }
+    for(int i=2;i<=n;i+=2)
+    {
+        cout<<i<<" ";
+    }
+    for(int i=1;i<=n;i+=2)
+    {
+        cout<<i<<" ";
+    }
+    return;
+}
+
+int32_t main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    solve();
+    return 0;
+}