Submission #147024

#	Time	Username	Problem	Language	Result	Execution time	Memory
147024		jun6873	City Mapping (NOI18_citymapping)	C++11	57 / 100	7 ms	1528 KiB

citymapping

#include "citymapping.h"
#include <bits/stdc++.h>
using namespace std;

// long long get_distance(int X, int Y);

using lint = long long;
const lint inf = 1e18;

int n, t=0, *A, *B, *W;

void f(vector<int> v) {
    int y = v[v.size()-1], z = v[0];
    vector<lint> a, b, c, d;

    lint mxd;

    mxd = 0;
    for (int i : v) {
        lint d = get_distance(y, i);
        if (d > mxd) mxd = d, z = i;
        b.push_back(d);
    }

    for (int i : v) c.push_back(get_distance(z, i));
    for (int i=0; i<v.size(); i++) d.push_back(b[i] - c[i]);

    vector<int> ind;
    for (int i=0; i<v.size(); i++) ind.push_back(i);
    sort(ind.begin(), ind.end(), [&](int x, int y) { return (d[x] < d[y]) or (d[x] == d[y] and b[x] < b[y]); });

    vector<lint> tb, td;
    vector<int> tv;

    for (int i=0; i<b.size(); i++) tb.push_back(b[ind[i]]);
    b = tb;
    for (int i=0; i<d.size(); i++) td.push_back(d[ind[i]]);
    d = td;
    for (int i=0; i<v.size(); i++) tv.push_back(v[ind[i]]);
    v = tv;

    for (int i=0; i<v.size(); ) {
        vector<int> u;
        int k = i;
        while (i+1<v.size() and d[i] == d[i+1]) {
            u.push_back(i+1);
            i++;
        } i++;
        if (i < v.size()) {
            A[t] = v[k]; B[t] = v[i]; W[t] = b[i] - b[k]; t++;
        }
        if (!u.empty()) {
            A[t] = v[k]; B[t] = v[u[0]]; W[t] = b[u[0]] - b[k]; t++;
        }
        if (u.size() >= 2) {
            for (int &i : u) i = v[i];
            f(u);
        }
    }
}

void find_roads(int N, int Q, int a[], int b[], int w[]) {
    n = N; A = a; B = b; W = w;
    vector<int> v;
    for (int i=1; i<=n; i++) v.push_back(i);

    lint mx = 0;
    int k;
    for (int i=2; i<=n; i++) {
        lint now = get_distance(1, i);
        if (now > mx) {
            mx = now;
            k = i;
        }
    }
    swap(v[k-1], v[n-1]);

    f(v);
}

Compilation message (stderr)

citymapping.cpp: In function 'void f(std::vector<int>)':
citymapping.cpp:26:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<v.size(); i++) d.push_back(b[i] - c[i]);
                   ~^~~~~~~~~
citymapping.cpp:29:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<v.size(); i++) ind.push_back(i);
                   ~^~~~~~~~~
citymapping.cpp:35:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<b.size(); i++) tb.push_back(b[ind[i]]);
                   ~^~~~~~~~~
citymapping.cpp:37:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<d.size(); i++) td.push_back(d[ind[i]]);
                   ~^~~~~~~~~
citymapping.cpp:39:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<v.size(); i++) tv.push_back(v[ind[i]]);
                   ~^~~~~~~~~
citymapping.cpp:42:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<v.size(); ) {
                   ~^~~~~~~~~
citymapping.cpp:45:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while (i+1<v.size() and d[i] == d[i+1]) {
                ~~~^~~~~~~~~
citymapping.cpp:49:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (i < v.size()) {
             ~~^~~~~~~~~~
citymapping.cpp: In function 'void find_roads(int, int, int*, int*, int*)':
citymapping.cpp:76:13: warning: 'k' may be used uninitialized in this function [-Wmaybe-uninitialized]
     swap(v[k-1], v[n-1]);
            ~^~

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