#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef long double ld; typedef pair<int, int> pii; typedef pair<ll, ll> pll; typedef vector<bool> vb; typedef vector<int> vi; typedef vector<vector<int>> vvi; typedef vector<ll> vl; typedef vector<vector<ll>> vvl; #define pb push_back #define eb emplace_back #define mp make_pair #define mt make_tuple #define st first #define nd second #define FOR(__VAR, __START, __END) for(int __VAR=__START; __VAR<=__END; __VAR++) #define FORB(__VAR, __START, __END) for(int __VAR=__START; __VAR>=__END; __VAR--) #define FORK(__VAR, __START, __END, __DIFF) for(int __VAR=__START; __VAR<=END; __VAR+=__DIFF) #define all(__VAR) (__VAR).begin(), (__VAR).end() #define rall(__VAR) (__VAR).rbegin(), (__VAR).rend() #define DEBUG(__VAR) cout << #__VAR << ": " << __VAR << endl; template<typename __T1, typename __T2> ostream & operator<<(ostream &out, pair<__T1, __T2> &__VAR) { cout << "[" << __VAR.st << ", " << __VAR.nd << "]"; return out; } template<typename __T> ostream & operator<<(ostream &out, vector<__T> &__VAR) { cout << "["; FOR(i, 0, (int)__VAR.size()-2) cout << __VAR[i] << ", "; if(__VAR.size()>0) cout << __VAR[__VAR.size()-1]; cout << "]" << endl; return out; } const ll INF=1e17; //dynamiczne min na przedziale class segmentTree { private: ll treeSize=1; vector<ll> v; ll getMin(ll left, ll right, ll cur, ll p, ll q) { if(right<p || q<left) return INF; if(p<=left && right<=q) return v[cur]; ll mid=(left+right)/2LL; return min(getMin(left,mid,2*cur,p,q),getMin(mid+1,right,2*cur+1,p,q)); } public: segmentTree() {} segmentTree(ll N) { while(treeSize<N) treeSize*=2; v.resize(2*treeSize, INF); } ll getMin(ll p, ll q) { return getMin(1,treeSize,1,p,q); } void insert(ll pos, ll val) { pos+=treeSize-1; v[pos]=min(v[pos],val); while(pos/=2LL) v[pos]=min(v[2*pos],v[2*pos+1]); } }; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); ll n; cin >> n; vector<ll> pref(n+1, 0LL), dp(n+1, INF), a(n+1, 0LL); dp[0]=0; vector<pll> ind(1, {1LL,0}); for(int i=1; i<=n; i++) { cin >> a[i]; pref[i]=pref[i-1]+a[i]; ind.pb({pref[i]+1LL,0}); } sort(ind.begin(), ind.end()); auto last=unique(ind.begin(), ind.end()); ind.erase(last, ind.end()); for(ll i=0; i<ind.size(); i++) ind[i].nd=i+1LL; segmentTree tree(ind.size()); auto it=lower_bound(ind.begin(), ind.end(), mp(1LL,0LL)); tree.insert(it->nd, -1LL); for(ll i=1; i<=n; i++) { if(pref[i]<0LL) { dp[i]=INF; continue; } if(a[i]>=0LL) dp[i]=dp[i-1]; it=lower_bound(ind.begin(), ind.end(), mp((ll)(pref[i]+1LL), 0LL)); dp[i]=min(dp[i], tree.getMin(1LL, it->nd)+i); tree.insert(it->nd, dp[i]-i-1LL); //cout << i << ". " << pref[i] << " : " << (*it) << ": " << dp[i] << endl; //cout << i << ". insert: " << it->nd << ": " << dp[i]-i-1LL << endl; } /*for(ll i=1; i<=n; i++) { if(dp[i]<INF) cout << dp[i] << ' '; else cout << "INF "; } cout << endl;*/ if(pref[n]>=0LL) cout << dp[n] << '\n'; else cout << -1 << '\n'; return 0; }
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | #include <bits/stdc++.h> using namespace std; typedef long long ll; typedef long double ld; typedef pair<int, int> pii; typedef pair<ll, ll> pll; typedef vector<bool> vb; typedef vector<int> vi; typedef vector<vector<int>> vvi; typedef vector<ll> vl; typedef vector<vector<ll>> vvl; #define pb push_back #define eb emplace_back #define mp make_pair #define mt make_tuple #define st first #define nd second #define FOR(__VAR, __START, __END) for(int __VAR=__START; __VAR<=__END; __VAR++) #define FORB(__VAR, __START, __END) for(int __VAR=__START; __VAR>=__END; __VAR--) #define FORK(__VAR, __START, __END, __DIFF) for(int __VAR=__START; __VAR<=END; __VAR+=__DIFF) #define all(__VAR) (__VAR).begin(), (__VAR).end() #define rall(__VAR) (__VAR).rbegin(), (__VAR).rend() #define DEBUG(__VAR) cout << #__VAR << ": " << __VAR << endl; template<typename __T1, typename __T2> ostream & operator<<(ostream &out, pair<__T1, __T2> &__VAR) { cout << "[" << __VAR.st << ", " << __VAR.nd << "]"; return out; } template<typename __T> ostream & operator<<(ostream &out, vector<__T> &__VAR) { cout << "["; FOR(i, 0, (int)__VAR.size()-2) cout << __VAR[i] << ", "; if(__VAR.size()>0) cout << __VAR[__VAR.size()-1]; cout << "]" << endl; return out; } const ll INF=1e17; //dynamiczne min na przedziale class segmentTree { private: ll treeSize=1; vector<ll> v; ll getMin(ll left, ll right, ll cur, ll p, ll q) { if(right<p || q<left) return INF; if(p<=left && right<=q) return v[cur]; ll mid=(left+right)/2LL; return min(getMin(left,mid,2*cur,p,q),getMin(mid+1,right,2*cur+1,p,q)); } public: segmentTree() {} segmentTree(ll N) { while(treeSize<N) treeSize*=2; v.resize(2*treeSize, INF); } ll getMin(ll p, ll q) { return getMin(1,treeSize,1,p,q); } void insert(ll pos, ll val) { pos+=treeSize-1; v[pos]=min(v[pos],val); while(pos/=2LL) v[pos]=min(v[2*pos],v[2*pos+1]); } }; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); ll n; cin >> n; vector<ll> pref(n+1, 0LL), dp(n+1, INF), a(n+1, 0LL); dp[0]=0; vector<pll> ind(1, {1LL,0}); for(int i=1; i<=n; i++) { cin >> a[i]; pref[i]=pref[i-1]+a[i]; ind.pb({pref[i]+1LL,0}); } sort(ind.begin(), ind.end()); auto last=unique(ind.begin(), ind.end()); ind.erase(last, ind.end()); for(ll i=0; i<ind.size(); i++) ind[i].nd=i+1LL; segmentTree tree(ind.size()); auto it=lower_bound(ind.begin(), ind.end(), mp(1LL,0LL)); tree.insert(it->nd, -1LL); for(ll i=1; i<=n; i++) { if(pref[i]<0LL) { dp[i]=INF; continue; } if(a[i]>=0LL) dp[i]=dp[i-1]; it=lower_bound(ind.begin(), ind.end(), mp((ll)(pref[i]+1LL), 0LL)); dp[i]=min(dp[i], tree.getMin(1LL, it->nd)+i); tree.insert(it->nd, dp[i]-i-1LL); //cout << i << ". " << pref[i] << " : " << (*it) << ": " << dp[i] << endl; //cout << i << ". insert: " << it->nd << ": " << dp[i]-i-1LL << endl; } /*for(ll i=1; i<=n; i++) { if(dp[i]<INF) cout << dp[i] << ' '; else cout << "INF "; } cout << endl;*/ if(pref[n]>=0LL) cout << dp[n] << '\n'; else cout << -1 << '\n'; return 0; } |