Submission #747976

#	Time	Username	Problem	Language	Result	Execution time	Memory
747976		saayan007	City Mapping (NOI18_citymapping)	C++17	25 / 100	58 ms	8300 KiB

citymapping

#include "bits/stdc++.h"
#include "citymapping.h"
using namespace std;
using ll = long long;
#define fr first
#define sc second
#define eb emplace_back
#define nl endl

ll dist[1001][1001];

ll qry(int x, int y) {
    if(dist[x][y] != -1) return dist[x][y];
    dist[x][y] = abs(get_distance(x, y));
    dist[y][x] = dist[x][y];
    return dist[x][y];
}

void find_roads(int N, int Q, int A[], int B[], int W[]) {
    if(Q == 1200) {
        for(int i = 1; i <= N; ++i) {
            for(int j = 1; j <= N; ++j) {
                dist[i][j] = (i == j ? 0 : -1);
            }
        }

        vector<pair<int, ll>> adj[N + 1];
        int x = 2;
        for(int i = 2; i <= N; ++i) {
            if(qry(1, i) < qry(1, x)) x = i;
        }
        /* cout << 1 << ' ' << x << nl; */
        adj[1].eb(x, qry(1, x));
        adj[x].eb(1, qry(1, x));
        vector<pair<ll, int>> right, left;
        for(int i = 1; i <= N; ++i) {
            if(i == 1 || i == x) continue;
            if(qry(1, i) > qry(x, i)) right.eb(qry(x, i), i);
            else left.eb(qry(1, i), i);
        }
        sort(left.begin(), left.end());
        sort(right.begin(), right.end());
        /* for(auto [t, i] : left) cout << t << "," << i << ' '; cout << nl; */
        /* for(auto [t, i] : right) cout << t << ',' << i << ' '; cout << nl; */

        int m = left.size();
        if(m) {
            int y = left[0].sc;
            adj[y].eb(1, qry(1, y));
            adj[1].eb(y, qry(1, y));
            for(int i = 1; i < m; ++i) {
                y = left[i].sc;
                int z = left[i - 1].sc;
                adj[y].eb(z, qry(1, y) - qry(1, z));
                adj[z].eb(y, qry(1, y) - qry(1, z));
            }
        }

        m = right.size();
        if(m) {
            int y = right[0].sc;
            adj[y].eb(x, qry(x, y));
            adj[x].eb(y, qry(x, y));
            for(int i = 1; i < m; ++i) {
                y = right[i].sc;
                int z = right[i - 1].sc;
                adj[y].eb(z, qry(x, y) - qry(x, z));
                adj[z].eb(y, qry(x, y) - qry(x, z));
            }
        }

        int ptr = 0;
        for(int i = 1; i <= N; ++i) {
            for(auto [j, w] : adj[i]) {
                if(i < j) continue;
                A[ptr] = i; B[ptr] = j; W[ptr] = w;
                ++ptr;
            }
        }
        return;
    }
    ll other_dist[N + 1][N + 1];
    for(int i = 1; i <= N; ++i) {
        other_dist[i][i] = 0;
        for(int j = i + 1; j <= N; ++j) {
            other_dist[i][j] = other_dist[j][i] = abs(get_distance(i, j));
        }
    }
    /* for(int i = 1; i <= N; ++i) { */
    /*     for(int j = 1; j <= N; ++j) { */
    /*         cout << other_dist[i][j] << ' '; */
    /*     } */
    /*     cout << nl; */
    /* } */
    /* cout << nl; */
 
    vector<pair<int, ll>> adj[N + 1];
    for(int i = 1; i <= N; ++i) {
        int x = (i == 1 ? 2 : 1);
        for(int j = 1; j <= N; ++j) {
            if(j == i) continue;
            if(other_dist[i][j] < other_dist[i][x]) x = j;
        }
        adj[i].eb(x, other_dist[i][x]);
 
        int y = 0;
        for(int j = 1; j <= N; ++j) {
            if(j == i || j == x) continue;
            if(other_dist[i][j] == other_dist[i][x] + other_dist[x][j]) continue;
            if(y == 0 || other_dist[i][j] < other_dist[i][y]) y = j;
        }
        if(y == 0) continue;
        adj[i].eb(y, other_dist[i][y]);
        /* continue; */
 
        int z = 0;
        for(int j = 1; j <= N; ++j) {
            if(j == i || j == x || j == y) continue;
            if(other_dist[i][j] == other_dist[i][x] + other_dist[x][j]) continue;
            if(other_dist[i][j] == other_dist[i][y] + other_dist[y][j]) continue;
            if(z == 0 || other_dist[i][j] < other_dist[i][z]) z = j;
        }
        if(z == 0) continue;
        adj[i].eb(z, other_dist[i][z]);
    }
 
    int ptr = 0;
    for(int i = 1; i <= N; ++i) {
        for(auto [j, w] : adj[i]) {
            if(j <= i) continue;
            A[ptr] = i; B[ptr] = j; W[ptr] = w;
            ++ptr;
            /* cout << i << ' ' << j << ' ' << w << nl; */
        }
    }
    return;
}

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