Submission #113873

#	Time	Username	Problem	Language	Result	Execution time	Memory
113873		baluteshih	Shortcut (IOI16_shortcut)	C++14	97 / 100	2051 ms	63096 KiB

shortcut

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define pb push_back
#define jizz ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define F first
#define S second
#define ET cout << "\n"
#define MP make_pair
#define MEM(i,j) memset(i,j,sizeof i)
#define ALL(v) v.begin(),v.end()
#define DB(a,s,e) {for(int i=s;i<e;++i) cout << a[i] << " ";ET;}
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

const ll INF=1e18;

/*
j<i
si-sj+di+dj>k
si+di-k>sj-dj

x-y<0
|sj-x|+|si-y|+di+dj+c<=k 
x+y>=(sj+dj)+(si+di)-k+c ->b0
x-y>=(sj+dj)-(si-di)-k+c ->b1
x-y<=(sj-dj)-(si+di)+k-c ->b2
x+y<=(sj-dj)+(si-di)+k-c ->b3

y>=b0-x
y>=x-b2
y<=x-b1
y<=b3-x
y<=sn

*/

ll bit[2][1000005];
vector<ll> vec;

void modify(ll x,ll v)
{
	for(;x<=vec.size();x+=x&-x) bit[0][x]=max(bit[0][x],v);
}

ll query(ll x)
{
	ll re;
	for(re=-INF;x;x-=x&-x) re=max(re,bit[0][x]);
	return re;
}

ll find_shortcut(int n,vector<int> l,vector<int> d, int c)
{
	ll mx=-INF,L=1,R=0;
	vector<ll> s(n,0),dp(n,0),idx(n,0);
	for(int i=1;i<n;++i)
		s[i]=s[i-1]+l[i-1];
	for(int i=0;i<n;++i)
		dp[i]=max((ll)d[i],s[i]+mx),mx=max(mx,dp[i]-s[i]);
	for(int i=1;i<n;++i)
		R=max(R,dp[i-1]+d[i]+s[i]-s[i-1]);
	for(int i=0;i<n;++i)
		vec.pb(s[i]-d[i]);
	sort(ALL(vec)),vec.resize(unique(ALL(vec))-vec.begin());
	for(int i=0;i<n;++i)
		idx[i]=upper_bound(ALL(vec),s[i]-d[i])-vec.begin();
	while(L<R)
	{
		ll mid=L+R>>1,mit=INF,b0=-INF,b1=-INF,b2=-1,b3=INF,flag=0;
		for(int i=1;i<=vec.size();++i)
			bit[0][i]=-INF,bit[1][i]=INF;
		for(int i=1;i<n;++i)
		{
			modify(idx[i-1],s[i-1]+d[i-1]),mit=min(mit,s[i-1]-d[i-1]);
			ll p=lower_bound(ALL(vec),s[i]+d[i]-mid)-vec.begin(),mx=query(p),mi=mit<s[i]+d[i]-mid?mit:INF;
			b0=max(b0,s[i]+d[i]+mx-mid+c),b1=max(b1,mx-s[i]+d[i]-mid+c);
			b2=min(b2,mi-s[i]-d[i]+mid-c),b3=min(b3,mi+s[i]-d[i]+mid-c);
		}
		for(int i=0,j=n,k=0;i+1<n&&!flag;++i)
		{
			ll up=min({s[n-1],s[i]-b1,b3-s[i]}),dn=max(b0-s[i],s[i]-b2);
			while(j>0&&s[j-1]>=b0-s[i]) --j;
			while(k<n&&s[k]<s[i]-b2) ++k;
			if(max(j,k)!=n&&s[max(j,k)]<=up) flag=1;
		}
		if(flag) R=mid;
		else L=mid+1;
	}
	return L;
}

Compilation message (stderr)

shortcut.cpp: In function 'void modify(ll, ll)':
shortcut.cpp:44:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(;x<=vec.size();x+=x&-x) bit[0][x]=max(bit[0][x],v);
       ~^~~~~~~~~~~~
shortcut.cpp: In function 'll find_shortcut(int, std::vector<int>, std::vector<int>, int)':
shortcut.cpp:71:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   ll mid=L+R>>1,mit=INF,b0=-INF,b1=-INF,b2=-1,b3=INF,flag=0;
          ~^~
shortcut.cpp:72:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=1;i<=vec.size();++i)
               ~^~~~~~~~~~~~
shortcut.cpp:83:40: warning: unused variable 'dn' [-Wunused-variable]
    ll up=min({s[n-1],s[i]-b1,b3-s[i]}),dn=max(b0-s[i],s[i]-b2);
                                        ^~

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 33 / 33
• Subtask 6: 22 / 22
• Subtask 7: 4 / 4
• Subtask 8: 0 / 3