#include <bits/stdc++.h> //Michał Kuśmirek using namespace std; //XIII LO Szczecin #define FOR(i, a, b) for(int i = (a); i <= (b); ++i) #define REP(i, n) for(int i = 0; i < (n); ++i) using ll = long long; using pii = pair<int, int>; template<class T> int size(T && a) { return (int)(a.size()); } ostream& operator << (ostream &os, string str) { for(char c : str) os << c; return os; } template <class A, class B> ostream& operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << "," << p.second << ')'; } template <class T> auto operator << (ostream &os, T &&x) -> decltype(x.begin(), os) { os << '{'; for(auto it = x.begin(); it != x.end(); ++it) os << *it << (it == prev(x.end()) ? "" : " "); return os << '}'; } template <class T> ostream& operator << (ostream &os, vector<vector<T>> vec) { for(auto x : vec) os << "\n " << x; return os; } void dump() {} template <class T, class... Args> void dump(T &&x, Args... args) { cerr << x << "; "; dump(args...); } #ifdef DEBUG # define debug(x...) cerr << "[" #x "]: ", dump(x), cerr << '\n' #else # define debug(...) 0 #endif //-------------------------------------------------- void solve() { int n; cin >> n; string s; cin >> s; int pref = 0; while(pref < n and s[pref] == '0') ++pref; int suf = 0; while(suf < n and s[n - 1 - suf] == '0') ++suf; priority_queue<pair<int, int>> Q; Q.push(pair(2 * pref, 2)); if(pref != n) Q.push(pair(2 * suf, 2)); int block = 0; FOR(i, pref, n - 1) { if(s[i] == '0') ++block; else { Q.push(pair(block, 1)); block = 0; } } int it = 0; int ans = 0; while(!Q.empty() and 2 * it < Q.top().first) { auto [x, p] = Q.top(); Q.pop(); int len = (x - 2 * it) / p; ans += len; ++it; if(p == 1) { if(len > 1) --ans; ++it; } } cout << n - ans << '\n'; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int T; cin >> T; while(T--) solve(); }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | #include <bits/stdc++.h> //Michał Kuśmirek using namespace std; //XIII LO Szczecin #define FOR(i, a, b) for(int i = (a); i <= (b); ++i) #define REP(i, n) for(int i = 0; i < (n); ++i) using ll = long long; using pii = pair<int, int>; template<class T> int size(T && a) { return (int)(a.size()); } ostream& operator << (ostream &os, string str) { for(char c : str) os << c; return os; } template <class A, class B> ostream& operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << "," << p.second << ')'; } template <class T> auto operator << (ostream &os, T &&x) -> decltype(x.begin(), os) { os << '{'; for(auto it = x.begin(); it != x.end(); ++it) os << *it << (it == prev(x.end()) ? "" : " "); return os << '}'; } template <class T> ostream& operator << (ostream &os, vector<vector<T>> vec) { for(auto x : vec) os << "\n " << x; return os; } void dump() {} template <class T, class... Args> void dump(T &&x, Args... args) { cerr << x << "; "; dump(args...); } #ifdef DEBUG # define debug(x...) cerr << "[" #x "]: ", dump(x), cerr << '\n' #else # define debug(...) 0 #endif //-------------------------------------------------- void solve() { int n; cin >> n; string s; cin >> s; int pref = 0; while(pref < n and s[pref] == '0') ++pref; int suf = 0; while(suf < n and s[n - 1 - suf] == '0') ++suf; priority_queue<pair<int, int>> Q; Q.push(pair(2 * pref, 2)); if(pref != n) Q.push(pair(2 * suf, 2)); int block = 0; FOR(i, pref, n - 1) { if(s[i] == '0') ++block; else { Q.push(pair(block, 1)); block = 0; } } int it = 0; int ans = 0; while(!Q.empty() and 2 * it < Q.top().first) { auto [x, p] = Q.top(); Q.pop(); int len = (x - 2 * it) / p; ans += len; ++it; if(p == 1) { if(len > 1) --ans; ++it; } } cout << n - ans << '\n'; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int T; cin >> T; while(T--) solve(); } |