Submission #1054027

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054027		nightfal	Stations (IOI20_stations)	C++17	5 / 100	517 ms	936 KiB

stations

// #include "stations.h"
#include <cstdio>
#include <iostream>
#include <cassert>
#include <map>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;

template <typename T> void print(T elem) {cout << elem << " ";}
template <typename T> void print(vector<T> &v) {for(auto elem: v) print(elem); cout << endl;};
template <typename T> void print(vector<vector<T>> &v) {for(auto elem: v) print(elem); cout << endl;};

// bool subtask1(int k, vector<vector<int>> &g) {
//     int n = g.size();
//     for(auto elem: g)
//         if (elem.size() > 2) return false;
//     if (k==1'000) return true;
// 	else return false;
// }
// bool subtask2(int k, vector<int> &u, vector<int> &v) {
//     int m = u.size();
//     for(int i=0; i<m; i++)
//         if (!(u[i]==i+1 && v[i]==i/2 || u[i]==i/2 && v[i]==i+1))
//             return false;
//     if (k==1'000) return true;
// 	else return false;
// }
// bool subtask3(int k, vector<vector<int>> &g) {
//     int n=g.size(), cnt=0;
//     for(auto elem: g)
//         if(elem.size()>2) cnt++;
//     if (cnt==1 && k==1'000'000) return true;
//     return false;
// }
// bool subtask4(int n, int k) {
// 	if (n<=8 && k==1'000'000'000) return true;
// 	else return false;
// }

bool DecideLabelsSubtask(int n, int k, vector<vector<int>> &g, vector<int> &u, vector<int> &v) {
	if (k==pow(10,9)) return 4;
	else if (k==pow(10,6)) return 3;
	for(auto elem: g)
		if(elem.size()>2) return 2;
	return 1;
}
void labelsSubtask1(int n, vector<vector<int>> &g, vector<int> &labels) {
	int node = 0;
	for (int i=0; i<n; i++)
		if(g[i].size()==1) node = i;

	for (int i=0; i<n; i++) {
		labels[node] = i;
		for(int next: g[node])
			if(labels[next]== -1) {node = next;}
	}
	return;
}
void labelsSubtask2(int n, vector<int> &labels) {
	for(int i=0; i<n; i++)
		labels[i] = i;
	return;
}
void genLabels3(int key, int node, vector<vector<int>> &g, vector<int> &labels) {
    labels[node]=key*1000+1;
    for(int i=2; i<1000; i++) {
        bool terminal = true;
        for(int next: g[node]) {
            if(labels[next]==-1) {labels[next] = 1000*key+i; node = next; terminal=false;}
        }
        if (terminal) return;
    }
}
void labelsSubtask3(int n, vector<vector<int>> &g, vector<int> &labels) {
	int root = 0;
	for(int i=0; i<n; i++)
		if(g[i].size() > 2)  {root = i; break;}
		labels[root] = 1000;
	for(int i=0; i<g[root].size(); i++) {
		int child = g[root][i];
		genLabels3(i+1, child, g, labels);
	} 
	return;
}
void genLabels4(int base, int key, int exp, int node, vector<vector<int>> &g, vector<int> &labels) {
    labels[node]=base + key*pow(10,exp);
	base = labels[node];

    for(int i=1; i<=g[node].size(); i++) {
		int child = g[node][i];
		if (labels[child]==-1) 
        	genLabels4(base,i,exp-1, child, g, labels);
    }
	return;
}
void labelsSubtask4(int n, vector<vector<int>> &g, vector<int> &labels) {
	labels[0] = 100'000'000;
	int base = labels[0];
	for(int i=1; i<=g[0].size(); i++) {
		int child = g[0][i];
		genLabels4(base,i,7, child, g, labels);
	}	
}
std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	std::vector<int> labels(n,-1);
    vector<vector<int>> g(n);
    for (int i=0; i<n-1; i++) {
        g[u[i]].push_back(v[i]);
        g[v[i]].push_back(u[i]);
    }
	int subtask = DecideLabelsSubtask(n,k,g,u,v);
	switch(subtask) {
		case 1: labelsSubtask1(n, g, labels); break;
    	case 2: labelsSubtask2(n,labels); break;
		case 3: labelsSubtask3(n,g,labels); break;
		case 4: labelsSubtask4(n,g,labels);
	}
    // print(labels);
	return labels;
}
bool ancestor(int s, int t) {
    if (s==0) return true;
    while (t) {
        if (s==t) return true;
        t = (t-1)>>1;
    }
    return false;
}
bool decideFindSubtask(int s, int t, vector<int> &c) {
	if (s>pow(10,6) || t>pow(10,6)) return 4;
    else if (s>1'000 || t>1'000) return 3;
	switch(s) {
		case 0:
			if (c.size()==1) return 1;
			else if (c.size()==2) return 2;
		case 1:
			if (t==0) return -1;
			else {
				for(int elem: c) 
					if(elem == 2) return 1;
				return 2;
			}
		default:
			for(int i=0; i<c.size(); i++)
				if(!(c[i]==s-1 || c[i]==s+1)) return 2;
			return 1;
	}
}
int find_next_station(int s, int t, std::vector<int> c) {
    int subtask = decideFindSubtask(s,t,c);

	switch(subtask) {
		case -1: return 0;
		case 1: 
	        for(int next: c)
    	        if (s<t && s<next) return next;
        	    else if (s>t && s>next) return next;
		case 2:
	        if (ancestor(2*s+1,t)) return 2*s+1;
    	    else if (ancestor(2*s+2,t)) return 2*s+2;
        	else return (s-1)/2;
		case 3:
			if (s==1000) return (t/1000)*1000+1;
			if (s/1000 == t/1000) {
				if (s<t) return s+1;
				else return s-1;
			}
			else { 
				if (s%1000==1) return 1000;
				else return s-1;
			}
		case 4: return 0;
	}
}

Compilation message (stderr)

stations.cpp: In function 'void labelsSubtask3(int, std::vector<std::vector<int> >&, std::vector<int>&)':
stations.cpp:78:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   78 |  for(int i=0; i<n; i++)
      |  ^~~
stations.cpp:80:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   80 |   labels[root] = 1000;
      |   ^~~~~~
stations.cpp:81:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |  for(int i=0; i<g[root].size(); i++) {
      |               ~^~~~~~~~~~~~~~~
stations.cpp: In function 'void genLabels4(int, int, int, int, std::vector<std::vector<int> >&, std::vector<int>&)':
stations.cpp:91:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |     for(int i=1; i<=g[node].size(); i++) {
      |                  ~^~~~~~~~~~~~~~~~
stations.cpp: In function 'void labelsSubtask4(int, std::vector<std::vector<int> >&, std::vector<int>&)':
stations.cpp:101:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  101 |  for(int i=1; i<=g[0].size(); i++) {
      |               ~^~~~~~~~~~~~~
stations.cpp: In function 'bool decideFindSubtask(int, int, std::vector<int>&)':
stations.cpp:146:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  146 |    for(int i=0; i<c.size(); i++)
      |                 ~^~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:176:1: warning: control reaches end of non-void function [-Wreturn-type]
  176 | }
      | ^

• Subtask 1: 5 / 5
• Subtask 2: 0 / 8
• Subtask 3: 0 / 16
• Subtask 4: 0 / 10
• Subtask 5: 0 / 61