42 lines
657 B
C++
42 lines
657 B
C++
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#include<bits/stdc++.h>
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using namespace std;
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using ll = long long;
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void solve()
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{
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int n;
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cin>>n;
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string s;
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cin>>s;
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unordered_map<char,int>m;
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int ct=0;
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for(int i=0; i<s.size(); ++i)
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{
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if(s[i]>='a' && s[i]<='z')
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{
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m[s[i]]++;
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}
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else
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{
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char c;
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c=tolower(s[i]);
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if(m[c]>0)
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{
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m[c]--;
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}
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else ct++;
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}
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}
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cout<<ct<<endl;
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}
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int main()
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{
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ios_base::sync_with_stdio(false);
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cin.tie(nullptr);
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int TC = 1;
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//cin >> TC;
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//cin.ignore();
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while (TC--) solve();
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}
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