added solutions by nikhil nagrale

Codeforces/112A_Petya_and_Strings.cpp

@@ -0,0 +1,13 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    string a,b;
+    cin>>a>>b;
+    for(auto &c: a) c=tolower(c);
+    transform(b.begin(),b.end(),b.begin(),::tolower);
+    cout<<a.compare(b)<<endl;
+    return 0;
+}

Codeforces/1328A_Divisibility_Problem.cpp

@@ -0,0 +1,19 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int t;
+    cin>>t;
+    while(t--){
+        long long a,b;
+        cin>>a>>b;
+        if(a%b==0)
+        cout<<0<<endl;
+        else{
+            cout<<b-a%b<<endl;
+        }
+    }
+    return 0;
+}

Codeforces/1389A_LCM_Problem.cpp

@@ -0,0 +1,16 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int t;
+    cin>>t;
+    while(t--){
+        int l,r;
+        cin>>l>>r;
+        if(2*l>r) cout<<"-1 "<<"-1"<<endl;
+        else cout<<l<<" "<<2*l<<endl;
+    }
+    return 0;
+}

Codeforces/148A_Insomnia_Cure.cpp

@@ -0,0 +1,20 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int a[4],d;
+    cin>>a[0]>>a[1]>>a[2]>>a[3]>>d;
+    int j;
+    set<int> s;
+    for(int i=0;i<4;i++){
+        j=1;
+        while(a[i]*j<=d){
+            if(a[i]*j<=d) s.insert(a[i]*j);
+            j++;
+        }
+    }
+    cout<<s.size()<<endl;
+    return 0;
+}

Codeforces/200B_Drinks.cpp

@@ -0,0 +1,18 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int n;
+    cin>>n;
+    double a[n];
+    double ans=0;
+    for(int i=0;i<n;i++){
+        cin>>a[i];
+        ans+=a[i];
+    }
+    cout<<ans/n<<endl;
+
+    return 0;
+}

Codeforces/266B_Queue_at_the_School.cpp

@@ -0,0 +1,20 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main() {
+    int n,t;
+    cin>>n>>t;
+    string a;
+    cin>>a;
+    while(t--){
+        for(int i=0;i<n-1;i++)
+        if(a[i]=='B' && a[i+1]=='G') {
+            swap(a[i],a[i+1]);
+            i++;
+        }
+    }
+    cout<<a<<endl;
+    return 0;
+}

Codeforces/271A_Beautiful_Year.cpp

@@ -0,0 +1,35 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include <bits/stdc++.h>
+using namespace std;
+
+bool areDistinct(int n)
+{
+    map<int, int> dis;
+    int digit;
+    while (n)
+    {
+        digit = n % 10;
+        if (dis[digit])
+        {
+            return false;
+        }
+        dis[digit] = 1;
+        n /= 10;
+    }
+    return true;
+}
+int main()
+{
+    int n;
+    cin >> n;
+    while (++n)
+    {
+        if (areDistinct(n))
+        {
+            cout << n << endl;
+            break;
+        }
+    }
+    return 0;
+}

Codeforces/41A_Translation.cpp

@@ -0,0 +1,15 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    string a,b;
+    cin>>a>>b;
+    for(int i=0;i<a.length()/2;i++){
+        swap(a[i],a[a.length()-1-i]);
+    }
+    if(a==b) cout<<"YES"<<endl;
+    else cout<<"NO"<<endl;
+    return 0;
+}

Codeforces/4A_Watermelon.cpp

@@ -0,0 +1,12 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int w;
+    cin>>w;
+    if(w%2==0 && w>2) cout<<"YES"<<endl;
+    else cout<<"NO"<<endl;
+    return 0;
+}

Codeforces/546A_Soldier_and_Bananas.cpp

@@ -0,0 +1,13 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    long long k,n,w;
+    cin>>k>>n>>w;
+    long long sum=((w*(w+1))/2)*k;
+    if(n>=sum) cout<<0<<endl;
+    else cout<<sum-n<<endl;
+    return 0;
+}

Codeforces/61A_Ultra_Fast_Mathematician.cpp

@@ -0,0 +1,20 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+    string a, b;
+    cin >> a >> b;
+    string v = "";
+    for (int i = 0; i < a.length(); i++)
+    {
+        if (a[i] == b[i])
+            v += "0";
+        else
+            v += "1";
+    }
+    cout << v << endl;
+    return 0;
+}

Codeforces/630A_Again_Twenty_Five!.cpp

@@ -0,0 +1,11 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+
+    long long n;
+
+    return 0;
+}

Codeforces/677A_Vanya_and_Fence.cpp

@@ -0,0 +1,20 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int n,h;
+    cin>>n>>h;
+    vector<int> v;
+    int temp;
+    int ans=0;
+    for(int i=0;i<n;i++){
+        cin>>temp;
+        if(temp>h)
+        ans+=2;
+        else ans++;
+    }
+    cout<<ans<<endl;
+    return 0;
+}

Codeforces/71A_Way_Too_Long_Words.cpp

@@ -0,0 +1,21 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int n;
+    cin>>n;
+    while(n--){
+        string s;
+        cin>>s;
+        if(s.length()>10){
+            string ans;
+            ans.push_back(s.front());
+            ans+=to_string(s.length()-2);
+            ans+=s.back();
+            cout<<ans<<endl;
+        }else cout<<s<<endl;
+    }
+    return 0;
+}

Codeforces/977A_Wrong_Subtraction.cpp

@@ -0,0 +1,15 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform else nknagrale
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int n,k;
+    cin>>n>>k;
+    while(k--){
+        if(n%10==0) n/=10;
+        else n--;
+    }
+    cout<<n<<endl;
+    return 0;
+}

Codeforces/996A_Hit_the_Lottery.cpp

@@ -0,0 +1,17 @@
+//code by Nikhil Nagrale
+//nikhilnagrale2 on EveryPlatform
+#include<bits/stdc++.h>
+using namespace std;
+
+int main(){
+    long long n;
+    cin>>n;
+    int ans=0;
+    int a[5]={100,20,10,5,1};
+    for(int x:a){
+        ans+=n/x;
+        n%=x;
+    }
+    cout<<ans<<endl;
+    return 0;
+}