Submission #376997

#	Time	Username	Problem	Language	Result	Execution time	Memory
376997		crackersamdjam	Rail (IOI14_rail)	C++17	30 / 100	169 ms	748 KiB

rail

#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()

#ifndef ONLINE_JUDGE
template<typename T>
void pr(T a){std::cerr<<a<<std::endl;}
template<typename T,typename... Args>
void pr(T a, Args... args) {std::cerr<<a<<' ',pr(args...);}
#else
template<typename... Args>
void pr(Args... args){}
#endif

using namespace std;

#ifdef LOCAL
// int nn = 4, ss[] = {2, 5, 3, 1}, tt[] = {2, 0, 2, 2};
int nn = 4, ss[] = {4, 1, 9, 2}, tt[] = {1, 1, 2, 2};
int ffirst = ss[0];
int dd[4][4] = {{0, 13, 5, 14}, {13, 0, 8, 1}, {5, 8, 0, 9}, {14, 1, 9, 0}};

int getDistance(int i, int j){
	assert(0 <= i and i < nn);
	assert(0 <= j and j < nn);
	return dd[i][j];
}
#else
#include "rail.h"
#endif

/*
4 4 1 1
1 1 1 1
9 9 2 2
0 2 1 2
*/

void findLocation(int n, int first, int loc[], int stype[]){
	array<int, 2> dis[n];
	dis[0] = {0, 0};
	loc[0] = first;
	stype[0] = 1;

	for(int i = 1; i < n; i++){
		dis[i] = {getDistance(0, i), i};
	}
	sort(dis, dis+n);
	auto [add, fs] = dis[1];
	int l = 0, r = fs;
	loc[fs] = first+add;
	stype[fs] = 2;
	pr("fs", fs, loc[fs]);

	for(int j = 2; j < n; j++){
		auto [d0, i] = dis[j];
		int df = getDistance(fs, i);
		pr(j, i, d0-add, df);
		if(d0-add == df){
			//then 0->i turns at fs
			// 0 ( 1
			// ( l 0 1
			// l ) 0 1
			if(df < add){
				// first case
				loc[i] = loc[fs]-df;
				stype[i] = 1;
				continue;
			}

			// now check it's distance from l to know which case (out of last two)
			int dl = getDistance(l, i);
			if(df == loc[fs]-loc[l] + dl){
				//it's l )
				loc[i] = loc[l]+dl;
				stype[i] = 2;
			}
			else{
				loc[i] = loc[fs]-df;
				stype[i] = 1;
				l = i;
			}
		}
		else{
			//it doesn't turn at fs
			// 0 1 ( r
			// 0 1 r )
			int dr = getDistance(r, i);
			// assert(d0 >= loc[r]-loc[0] + dr);
			if(d0 == loc[r]-loc[0] + dr){
				// 0 1 ( r
				loc[i] = loc[r]-dr;
				stype[i] = 1;
			}
			else{
				loc[i] = loc[0]+d0;
				stype[i] = 2;
				r = i;
			}
		}
		// dif = (d0 - (loc[r]-loc[0]) - dr)
		// if dif > 0, then it's somewhere on right
		// but if on right and dif = 0,
		// that means that d0 = dr + (loc[r]-loc[0])
		// let m be the point where r->i turns right
		// 0->m + m->r + r->i = dr + 0->m + m->r
		// r->i = dr
		// r->i = m<-r + m->r + r->i
		// m->r = 0]
		// so impossible
	}
}
/*
get all from station 0 and sort by distance
the first one is the first D right of 0
then loop through stations in sorted order,
compare dis(0, i) and dis(1st D, i) to see if on left or right side
then, to know if it's ( or ), query from most leftmost/rightmost existing one
*/

#ifdef LOCAL
int main(){
	int locations[nn], stype[nn];
	findLocation(nn, ffirst, locations, stype);
	for(int i = 0; i < nn; i++)
		cout<<locations[i]<<' ';
	cout<<'\n';
	for(int i = 0; i < nn; i++)
		cout<<stype[i]<<' ';
	cout<<'\n';	
}
#endif

• Subtask 1: 8 / 8
• Subtask 2: 22 / 22
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44