Submission #622829

#	Time	Username	Problem	Language	Result	Execution time	Memory
622829		PoonYaPat	City Mapping (NOI18_citymapping)	C++14	57 / 100	31 ms	8448 KiB

citymapping

#include "citymapping.h"

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,int> pii;
typedef tuple<int,int,int> t;

int n;
vector<int> v[1001];
vector<t> ans;
ll dis[1001][1001];

ll get(int  x, int y) {
    if (!dis[x][y]) dis[x][y]=dis[y][x]=get_distance(x,y);
    return dis[x][y];
}

void find(int x) {
    int r,l;
    ll longest=0;
    vector<pii> temp; //dis and node in backbone
    vector<int> tree;

    v[x].push_back(x);
    for (auto s : v[x]) if (get(x,s)>longest) longest=get(x,s), r=s;
    longest=0;
    for (auto s : v[x]) if (get(r,s)>longest) longest=get(r,s), l=s;
    for (auto s : v[x]) {
        if (r==s) continue;
        if (get(r,s)+get(s,l)==get(r,l)) temp.push_back(pii(get(r,s),s));
        else tree.push_back(s);
    }

    sort(temp.begin(),temp.end());
    ans.push_back(t(r,temp[0].second,temp[0].first));

    for (int i=1; i<temp.size(); ++i) {
        ans.push_back(t(temp[i-1].second,temp[i].second,temp[i].first-temp[i-1].first));
    }
    v[x].clear();
    for (auto s : tree) {
        for (auto b : temp) {
            if (dis[r][s]-(dis[r][s]+dis[s][l]-dis[r][l])/2==b.first) {
                v[b.second].push_back(s);
                dis[b.second][s]=dis[s][b.second]=(dis[r][s]+dis[s][l]-dis[r][l])/2;
                break;
            }
        }
    }

    for (auto s : temp) if (v[s.second].size()) find(s.second);
}

void find_roads(int N, int Q, int A[], int B[], int W[]) {
    n=N;
    for (int i=2; i<=n; ++i) v[1].push_back(i);
    find(1);

    for (int i=0; i<ans.size(); ++i) tie(A[i],B[i],W[i])=ans[i];
	return;
}

Compilation message (stderr)

citymapping.cpp: In function 'void find(int)':
citymapping.cpp:38:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |     for (int i=1; i<temp.size(); ++i) {
      |                   ~^~~~~~~~~~~~
citymapping.cpp: In function 'void find_roads(int, int, int*, int*, int*)':
citymapping.cpp:60:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for (int i=0; i<ans.size(); ++i) tie(A[i],B[i],W[i])=ans[i];
      |                   ~^~~~~~~~~~~
citymapping.cpp: In function 'void find(int)':
citymapping.cpp:44:56: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   44 |             if (dis[r][s]-(dis[r][s]+dis[s][l]-dis[r][l])/2==b.first) {
      |                                                ~~~~~~~~^
citymapping.cpp:44:56: warning: 'l' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 13 / 13
• Subtask 4: 19 / 19
• Subtask 5: 0 / 43