Submission #260101

#	Time	Username	Problem	Language	Result	Execution time	Memory
260101		user202729	Travelling Merchant (APIO17_merchant)	C++17	100 / 100	112 ms	3576 KiB

merchant

// 6
#ifndef LOCAL
#define NDEBUG 1
#endif
#include<bits/stdc++.h>

/*
struct Edge{int node, length;};
std::vector<std::vector<Edge>> add;
*/

int main(){
	std::ios::sync_with_stdio(0);std::cin.tie(0);
	int number, numEdge, numItem; std::cin>>number>>numEdge>>numItem;
	struct T{int buy, sell;};
	std::vector<std::vector<T>> cost(number, std::vector<T>(numItem));
	for(auto& it: cost)for(auto& [buy, sell]: it) std::cin>>buy>>sell;

	std::vector<std::vector<int>> time(number, std::vector<int>(number, INT_MAX/2));
	for(int _=0; _<numEdge; ++_){
		int first, sec, length; std::cin>>first>>sec>>length;
		--first;--sec;
		time[first][sec]=std::min(time[first][sec], length);
	}

	for(int k=0; k<number; ++k)
		for(int i=0; i<number; ++i)
			for(int j=0; j<number; ++j)
				time[i][j]=std::min(time[i][j], time[i][k]+time[k][j]);

	for(auto& it: time)for(auto& it: it){
		assert(it>=0);
		assert(it<=INT_MAX/2);
	}

	std::vector<std::vector<int>> maxProfit(number, std::vector<int>(number));
	for(int i=0; i<number; ++i)
		for(int j=0; j<number; ++j){
			int cur=0; // 0 is always achievable by doing nothing
			for(int item=0; item<numItem; ++item)
				if(cost[j][item].sell>=0 and cost[i][item].buy>=0)
					cur=std::max(cur, cost[j][item].sell-cost[i][item].buy);
			maxProfit[i][j]=cur;
		}

	struct V{ // A-B*epsilon (B>=0)
		int64_t value; // least bit=1 -> B=0

		bool operator<(V other) const{return value<other.value;}
		bool operator==(V other) const{return value==other.value;}
		V operator+(V other) const{return {value+other.value-((value|other.value)&1)};}
	};
	assert(V{1}+V{1}==V{1});
	assert(V{1}+V{0}==V{0});
	assert(V{0}+V{1}==V{0});
	assert(V{0}+V{0}==V{0});

	std::vector<std::vector<V>> tmp(number, std::vector<V>(number));
	auto const check=[&](int64_t efficient){
		for(int i=0; i<number; ++i)
			for(int j=0; j<number; ++j){
				int profit=maxProfit[i][j];
				if(i==j) assert(profit==0);
				int time_=time[i][j];
				tmp[i][j]=V{
					time_==INT_MAX/2 ? INT64_MAX/2:
					((time_*efficient-profit)*2+(profit==0))
				};
			}

		for(int k=0; k<number; ++k)
			for(int i=0; i<number; ++i)
				for(int j=0; j<number; ++j)
					tmp[i][j]=std::min(tmp[i][j], tmp[i][k]+tmp[k][j]);

		for(int i=0; i<number; ++i)
			if(tmp[i][i]<V{1})
				return true;
		return false;
	};

	int i=0;
	for(int step=1<<30; step; step>>=1){
		if(check(i+step)) i+=step;
	}
	std::cout<<i<<'\n';
}

Compilation message (stderr)

merchant.cpp: In function 'int main()':
merchant.cpp:31:31: warning: unused variable 'it' [-Wunused-variable]
  for(auto& it: time)for(auto& it: it){
                               ^~

• Subtask 1: 12 / 12
• Subtask 2: 21 / 21
• Subtask 3: 33 / 33
• Subtask 4: 34 / 34