Add solutions for Codeforces problems 1971A, 1971B, 1971C, 1971D, 1971E, and 1971F

Codes/1971 A - My First Sorting Problem/1971A.cpp

@@ -0,0 +1,24 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    ll x,y;
+    cin>>x>>y;
+    cout<<min(x,y)<<" "<<max(x,y)<<endl;
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}

Codes/1971 B - Different String/1971B.cpp

@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    string s;
+    cin>>s;
+    bool ok=0;
+    for(int i=1; i<s.size(); ++i)
+    {
+        if(s[i]!=s[0])
+        {
+            swap(s[i],s[0]);
+            ok=1;
+            break;
+        }
+    }
+    if(ok) cout<<"YES\n"<<s<<endl;
+    else cout<<"NO\n";
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}

Codes/1971 C - Clock and Strings/1971C.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    ll a,b,c,d;
+    cin>>a>>b>>c>>d;
+    int ct=0;
+    for(int i=min(a,b); i<=max(a,b); ++i)
+    {
+        if(i==c || i==d) ct++;
+    }
+    if(ct & 1)  cout<<"YES\n";
+    else cout<<"NO\n";
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}

Codes/1971 D - Binary Cut/1971D.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    string s;
+    cin>>s;
+    ll ans=1, f=0;
+    for(int i=1; i<s.size(); ++i)
+    {
+        ans += (s[i] != s[i-1]);
+        f |= (s[i]=='1' && s[i-1]=='0');
+    }
+    cout<<ans-f<<endl;
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}

Codes/1971 E - Find the Car/1971E.cpp

@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+void solve()
+{
+    ll n,k,q;
+    cin>>n>>k>>q;
+    vector<ll>a(k+1),b(k+1);
+    a[0]=b[0]=0;
+    for(int i=1; i<=k; ++i) cin>>a[i];
+    for(int i=1; i<=k; ++i) cin>>b[i];
+    while(q--)
+    {
+        ll d;
+        cin>>d;
+        ll ind=lower_bound(a.begin(),a.end(),d) - a.begin();
+        if(a[ind]==d)  cout<<b[ind]<<" ";
+        else
+        {
+            ll dist=a[ind]-a[ind-1];
+            ll time=b[ind]-b[ind-1];
+            ll x=d-a[ind-1];
+            cout<<((x*time)/dist)+b[ind-1]<<" ";
+        }
+    }
+    cout<<endl;
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}

Codes/1971 F - Circle Perimeter/1971F.cpp

@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define endl '\n'
+ll pow(ll x,ll y,ll m=1e9+7){ll ans=1;x%=m;while(y){if(y&1)ans=(ans*x)%m;x=(x*x)%m;y>>=1;}return ans;}
+
+ll points(ll r)
+{
+    ll p = 0;
+    for(ll x = 0; x <= r; ++x)
+    {
+        ll y,d = (r + 1) * (r + 1) - x * x;
+        ll l = 0, h = r;
+        while(l <= h)
+        {
+            ll mid = l + (h - l) / 2;
+            if(mid * mid < d)
+            {
+                y = mid;
+                l = mid + 1;
+            }
+            else    h = mid - 1;
+        }
+        if(x == 0)    p += (y * 2 + 1);
+        else    p += ((y * 2 + 1) * 2);
+    }
+    return p;
+}
+
+void solve()
+{
+    ll r;
+    cin >> r;
+    ll p1 = points(r);
+    ll p2 = points(r - 1);
+    cout << p1 - p2 << endl;
+}
+
+signed main()
+{
+    ios_base::sync_with_stdio(false), cin.tie(nullptr);
+    int TCS = 1;
+    cin >> TCS;
+    for (int TC = 1; TC <= TCS; ++TC)
+    {
+        // cout<<"Case "<<TC<<": ";
+        solve();
+    }
+}

Readme.md

@@ -319,6 +319,12 @@ This repository contains my solutions of Codeforces problems. They are in C++ la
 | 307 | 1968 G1 | Division + LCP (easy version) | [Question](https://codeforces.com/problemset/problem/1968/G1) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1968%20G1%20-%20Division%20+%20LCP%20(easy%20version))
 | 308 | 1969 A | Two Friends | [Question](https://codeforces.com/problemset/problem/1969/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1969%20A%20-%20Two%20Friends)
 | 309 | 1969 B | Shifts and Sorting | [Question](https://codeforces.com/problemset/problem/1969/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1969%20B%20-%20Shifts%20and%20Sorting)
+| 310 | 1971 A | My First Sorting Problem | [Question](https://codeforces.com/problemset/problem/1971/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1971%20A%20-%20My%20First%20Sorting%20Problem)
+| 311 | 1971 B | Different String | [Question](https://codeforces.com/problemset/problem/1971/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1971%20B%20-%20Different%20String)
+| 312 | 1971 C | Clock and Strings | [Question](https://codeforces.com/problemset/problem/1971/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1971%20C%20-%20Clock%20and%20Strings)
+| 313 | 1971 D | Binary Cut | [Question](https://codeforces.com/problemset/problem/1971/D) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1971%20D%20-%20Binary%20Cut)
+| 314 | 1971 E | Find the Car | [Question](https://codeforces.com/problemset/problem/1971/E) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1971%20E%20-%20Find%20the%20Car)
+| 315 | 1971 F | Circle Perimeter | [Question](https://codeforces.com/problemset/problem/1971/F) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1971%20F%20-%20Circle%20Perimeter)