added 1905C

Codes/1905C Largest Subsequence/1905C.cpp

@@ -0,0 +1,105 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+// Short forms
+#define int                 long long
+#define ll                  long long
+#define endl                '\n'
+#define ff                  first
+#define ss                  second
+#define pb                  push_back
+#define all(x)              x.begin(), x.end()
+#define sz(x)               (int)(x).size()
+
+// Outputs
+#define yes                 cout<<"YES"<<endl
+#define no                  cout<<"NO"<<endl
+
+// Constants
+#define PI                  3.141592653589793238
+#define INF                 LONG_LONG_MAX
+#define MOD                 1e9+7
+
+// Faster Input Output
+#define FAST_IO             (ios_base:: sync_with_stdio(false),cin.tie(NULL));
+
+// Maths
+ll fact(ll n)          { if(n==0) return 1; ll res = 1; for (ll i = 2; i <= n; i++) res = res * i; return res; }
+ll nPr(ll n, ll r)     { return fact(n) / fact(n - r); }
+ll nCr(ll n, ll r)     { return fact(n) / (fact(r) * fact(n - r)); }
+ll gcd(ll a, ll b)     { if (b == 0) return a; return gcd(b, a % b); }
+ll lcm(ll a, ll b)     { return (a * b) / gcd(a, b);}
+ll mypow(ll a, ll b)   { ll ans = 1; while(b){ if (b&1) ans = (ans*a) ; b /= 2; a = (a*a); } return ans; }
+bool isPrime(ll n)     { if(n <= 1) return false; for(ll i = 2; i <= sqrt(n); i++) if(n % i == 0) return false; return true; }
+
+//Debugging
+#ifndef ONLINE_JUDGE
+#define dbg(x) cerr << #x <<" "; _print(x); cerr << endl;
+#define dbgin(x) cerr << #x <<" "; _print(x); cerr << ";"<<endl;
+#else
+#define dbg(x)
+#define dbgin(x)
+#endif
+ 
+void _print(int t) {cerr << t;}void _print(string t) {cerr << t;}void _print(char t) {cerr << t;}
+void _print(long double t) {cerr << t;}void _print(double t) {cerr << t;}void _print(unsigned ll t) {cerr << t;}
+template <class T, class V> void _print(pair <T, V> p);
+template <class T> void _print(vector <T> v);template <class T> void _print(set <T> v);
+template <class T, class V> void _print(map <T, V> v);template <class T> void _print(multiset <T> v);
+template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.first); cerr << ","; _print(p.second); cerr << "}";}
+template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T> void _print(unordered_set <T> v) {cerr<<"[ "; for(T i : v) {_print(i); cerr<<" ";} cerr<<"]";}
+template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T, class V> void _print(multimap <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";} 
+template <class T, class V> void _print(unordered_map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+bool cmp(pair<char,int>a, pair<char,int>b)
+{
+    if(a.ff==b.ff)
+        return a.ss<b.ss;
+    return a.ff>b.ff;
+}
+
+void solve()
+{
+    int n;
+    string s;
+    cin>>n>>s;
+    vector<int>v;
+    for(int i=0; i<sz(s); ++i)
+    {
+        while(!v.empty() && s[v.back()]<s[i])
+            v.pop_back();
+        v.pb(i);
+    }
+    int ct=count(all(s),s[v[0]]);
+    for(int i=0; i<sz(v)/2; ++i)
+    {
+        swap(s[v[i]],s[v[sz(v)-i-1]]);
+    }
+    int sorted=1;
+    for(int i=1;i<sz(s);++i)
+    {
+        if(s[i]<s[i-1])
+        {
+            sorted=0;
+            break;
+        }
+    }
+    if(sorted)
+        cout<<sz(v)-ct<<endl;
+    else
+        cout<<-1<<endl;
+}
+
+int32_t main()
+{
+    FAST_IO;
+    int TC = 1;
+    cin >> TC;
+    while (TC--) solve();
+}

Readme.md

@@ -197,6 +197,7 @@ This repository contains my solutions of Codeforces problems. They are in C++ la
 | 1904A | Forked! | [Question](https://codeforces.com/problemset/problem/1904/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1904A%20Forked!)
 | 1905A | Constructive Problems | [Question](https://codeforces.com/problemset/problem/1905/A) | [Solution]
 | 1905B | Begginer's Zelda | [Question](https://codeforces.com/problemset/problem/1905/B) | [Solution]
+| 1905C | Largest Subsequence | [Question](https://codeforces.com/problemset/problem/1905/C) | [Solution]
 | 1907A | Rook | [Question](https://codeforces.com/problemset/problem/1907/A) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1907A%20Rook)
 | 1907B | YetnotherrokenKeoard | [Question](https://codeforces.com/problemset/problem/1907/B) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1907B%20YetnotherrokenKeoard)
 | 1907C | Removal of Unattractive Pairs | [Question](https://codeforces.com/problemset/problem/1907/C) | [Solution](https://github.com/ShazidMashrafi/Codeforces-Solutions/tree/master/Codes/1907C%20Removal%20of%20Unattractive%20Pairs)