Submission #840890

#TimeUsernameProblemLanguageResultExecution timeMemory
840890Charizard2021Bread First Search (CCO21_day2problem2)C++17
25 / 25
88 ms5936 KiB
#include<bits/stdc++.h> using namespace std; #define IOS ios::sync_with_stdio(false);; cin.tie(NULL) long long gcd(long long a, long long b){ return (b == 0 ? a : gcd(b, a % b)); } void selfMax(long long& a, long long b){ a = max(a, b); } void selfMin(long long& a, long long b){ a = min(a, b); } template<typename T> istream& operator>>(istream& in, vector<T>& a) {for(auto &x : a) in >> x; return in;}; template<typename T1, typename T2> istream& operator>>(istream& in, pair<T1, T2>& x) {return in >> x.first >> x.second;} template<typename T1, typename T2> ostream& operator<<(ostream& out, const pair<T1, T2>& x) {return out << x.first << ' ' << x.second;} template<typename T> ostream& operator<<(ostream& out, vector<T>& a) {for(auto &x : a) out << x << ' '; return out;}; template<typename T> ostream& operator<<(ostream& out, vector<vector<T> >& a) {for(auto &x : a) out << x << '\n'; return out;}; template<typename T1, typename T2> ostream& operator<<(ostream& out, vector<pair<T1, T2> >& a) {for(auto &x : a) out << x << '\n'; return out;}; /* Use DSU dsu(N); */ struct DSU { vector<long long> adj2; DSU(long long N) { adj2 = vector<long long>(N, -1); } // get representive component (uses path compression) long long get(long long x) { return adj2[x] < 0 ? x : adj2[x] = get(adj2[x]); } bool same_set(long long a, long long b) { return get(a) == get(b); } long long size(long long x) { return -adj2[get(x)]; } bool unite(long long x, long long y) { // union by size x = get(x), y = get(y); if (x == y) return false; if (adj2[x] > adj2[y]) swap(x, y); adj2[x] += adj2[y]; adj2[y] = x; return true; } }; /* Run with Bit<long long> BIT */ template <class T> class BIT { private: long long size; vector<T> bit; vector<T> arr; public: BIT(long long size) : size(size), bit(size + 1), arr(size) {} void set(long long ind, long long val) { add(ind, val - arr[ind]); } void add(long long ind, long long val) { arr[ind] += val; ind++; for (; ind <= size; ind += ind & -ind) { bit[ind] += val; } } T pref_sum(long long ind) { ind++; T total = 0; for (; ind > 0; ind -= ind & -ind) { total += bit[ind]; } return total; } }; /* Change Comb for specific Seg tree probs, but run with Seg<long long> Seg; */ template<class T> struct Seg { const T ID = 1e18; T comb(T a, T b) { return min(a,b); } long long n; vector<T> seg; void init(long long _n) { n = _n; seg.assign(2*n,ID); } void pull(long long p) { seg[p] = comb(seg[2*p],seg[2*p+1]); } void upd(long long p, T val) { seg[p += n] = val; for (p /= 2; p; p /= 2) pull(p); } T query(long long l, long long r) { T ra = ID, rb = ID; for (l += n, r += n+1; l < r; l /= 2, r /= 2) { if (l&1) ra = comb(ra,seg[l++]); if (r&1) rb = comb(seg[--r],rb); } return comb(ra,rb); } }; int main(){ int n, m; cin >> n >> m; int l[n]; int r[n]; for(int i = 0; i < n; i++){ l[i] = i; r[i] = i; } for(int i = 0; i < m; i++){ int a, b; cin >> a >> b; a--; b--; if(a > b){ swap(a, b); } r[a] = max(r[a], b); l[b] = min(l[b], a); } vector<int> prefSum(n, 0); for(int i = 1; i < n; i++){ prefSum[l[i]]++; prefSum[i]--; } int cur1 = 0; int cur2 = 0; vector<int> d(n, 0); if(r[0] > 0){ d[r[0]] = prefSum[0]; } for(int i = 0; i < n; i++){ cur1 += prefSum[i]; cur2 = max(cur2, r[i]); if(i >= r[0]){ d[i] = max(d[i], d[i - 1]); d[cur2] = max(d[cur2], d[i] + cur1); } } cout << n - d[n - 1] - 1 << "\n"; }
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