제출 #784915

#제출 시각아이디문제언어결과실행 시간메모리
784915YassirSalamaShortcut (IOI16_shortcut)C++14
0 / 100
1 ms348 KiB
#include "shortcut.h" #include<bits/stdc++.h> using namespace std; #define ll long long const ll MAXN=5100; const ll INF=1e9+10; #define dbg(x) cout<<"[ "<<#x<<" ] : "<<x<<endl; #define F first #define S second #define all(v) v.begin(),v.end() vector<long long> pref(MAXN+1,0); vector<int> D; pair<long long,long long> tree[4*MAXN]; void build(int node,int l,int r){ if(l==r){ tree[node].F=pref[l]+D[l]; tree[node].S=l; return; } int mid=(l+r)/2; build(node<<1,l,mid); build(node<<1|1,mid+1,r); tree[node].F=max(tree[node<<1].F,tree[node<<1|1].F); if(tree[node].F==tree[node<<1].F) tree[node].S=tree[node<<1].S; else tree[node].S=tree[node<<1|1].S; } int query(int node,int l,int r,int ql,int qr){ if(ql<=l&&r<=qr){ return tree[node].S; } int mid=(l+r)/2; int ans=0; int index=0; if(ql<=mid) { int x=query(node<<1,l,mid,ql,qr); if(pref[x]+D[x]>ans) { ans=pref[x]+D[x]; index=x; } } if(qr>mid){ int x=query(node<<1|1,mid+1,r,ql,qr); if(pref[x]+D[x]>ans) { ans=pref[x]+D[x]; index=x; } } return index; } long long find_shortcut(int n, vector<int> l, vector<int> d, int c) { D=d; if(n==2){ if(c<l[0]) return (long long)d[0]+c+(long long)d[1]; return (ll)d[0]+(ll)l[0]+(ll)d[1]; } for(long long i=0;i<n-1;i++){ pref[i+1]=pref[i]+l[i]; } build(1,0,n-1); vector<long long> left(MAXN+1,0); vector<long long> right(MAXN+1,0); left[0]=(ll)d[0]; long long first_node=0; for(long long i=1;i<n;i++){ if(d[i]>left[i-1]+l[i-1]) first_node=i; left[i]=max(left[i-1]+l[i-1],(ll)d[i]); } long long last_node=n-1; right[n-1]=d[n-1]; for(long long i=n-2;i>=0;i--){ if(d[i]>right[i+1]+l[i]&&i!=first_node) last_node=i; right[i]=max(right[i+1]+l[i],(ll)d[i]); } long long diameter=left[first_node]+right[first_node]; for(long long i=0;i<=n-1;i++){ for(long long j=i+1;j<=n-1;j++){ long long express=left[i]+c+right[j]; long long newdiameter=0; for(long long k=0;k<=n-1;k++){ newdiameter=max({newdiameter, min( (ll)abs(pref[j]-pref[k])+right[j]+(d[k]==right[j]&&k==j?0LL:d[k]) , (ll)right[j]+(ll)c+(ll)abs(pref[i]-pref[k])+(d[k]==right[j]&&k==j?0LL:d[k]) ) }); } for(long long k=n-1;k>=0;k--){ newdiameter=max({newdiameter, min( (ll)abs(pref[k]-pref[i])+left[i]+(d[k]==left[i]&&k==i?0:d[k]), (ll)left[i]+c+abs(pref[j]-pref[k])+(d[k]==left[i]&&k==i?0:d[k]) ) }); } long long ans=0; for(int x=i+1;x<j;x++){ int y=query(1,0,n-1,x,j-1); ans=max(ans,pref[y]-pref[x]+d[y]+d[x]); } diameter=min({max({ans,newdiameter,(ll)express}),(ll)diameter}); } } // cout<<c<<endl; return diameter; } // int main() // { // int n, c; // assert(2 == scanf("%d%d", &n, &c)); // std::vector<int> l(n - 1); // std::vector<int> d(n); // for (int i = 0; i < n - 1; i++) // assert(1 == scanf("%d", &l[i])); // for (int i = 0; i < n; i++) // assert(1 == scanf("%d", &d[i])); // long long t = find_shortcut(n, l, d, c); // printf("%lld\n", t); // return 0; // }

컴파일 시 표준 에러 (stderr) 메시지

shortcut.cpp: In function 'long long int find_shortcut(int, std::vector<int>, std::vector<int>, int)':
shortcut.cpp:71:15: warning: variable 'last_node' set but not used [-Wunused-but-set-variable]
   71 |     long long last_node=n-1;
      |               ^~~~~~~~~
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