Submission #713561

#	Time	Username	Problem	Language	Result	Execution time	Memory
713561		Stickfish	Cop and Robber (BOI14_coprobber)	C++17	100 / 100	909 ms	31300 KiB

coprobber

#include "coprobber.h"
#include <iostream>
#include <queue>
#include <cassert>
#include <bitset>
#include <vector>
using namespace std;

bitset<MAX_N> edg[MAX_N];
bitset<MAX_N> redg[MAX_N];
bitset<MAX_N> used[2][MAX_N];
bitset<MAX_N> trused[MAX_N];
int depth[2][MAX_N][MAX_N];
int n;
int C;
int pR = -1;

int start(int N, bool A[MAX_N][MAX_N]) {
    n = N;
    int deg[MAX_N];

    for (int i = 0; i < N; ++i) for (int j = 0; j < N; ++j) {
        edg[i][j] = redg[j][i] = A[i][j];
    }
    for (int i = 0; i < N; ++i)
        deg[i] = edg[i].count();
    for (int i = 0; i < N; ++i) for (int j = 0; j < N; ++j) {
        //bad_edg_cnt[0][i][j] = 1;
        //bad_edg_cnt[1][i][j] = deg[j];
        depth[1][i][j] = depth[0][i][j] = 1234567890;
    }
    queue<vector<int>> q;
    for (int i = 0; i < N; ++i) {
        //bad_edg_cnt[0][i][i] = bad_edg_cnt[1][i][i] = 0;
        q.push({0, i, i});
        q.push({1, i, i});
        used[0][i][i] = used[1][i][i] = trused[i][i] = 1;
    }
    int timer = 0;
    while (q.size()) {
        int t = q.front()[0];
        int u = q.front()[1];
        int v = q.front()[2];
        //cout << t << ' ' << u << ' ' << v << " | ";
        depth[t][u][v] = timer++;
        q.pop();
        if (t == 0) {
            for (int nv = redg[v]._Find_first(); nv < n; nv = redg[v]._Find_next(nv)) {
                if (!used[1][u][nv] && (used[0][u] & edg[nv]) == edg[nv]) {
                    //cout << "(1 " << u << ' ' << nv << ") ";
                    q.push({1, u, nv});
                    used[1][u][nv] = 1;
                }
            }
        } else {
            bitset<MAX_N> cedg = redg[u];
            cedg[u] = 1;
            cedg ^= cedg & trused[v];
            for (int nu = cedg._Find_first(); nu < n; nu = cedg._Find_next(nu)) {
                q.push({0, nu, v});
                used[0][nu][v] = trused[v][nu] = 1;
            }
        }
        //cout << endl;
    }
    for (int u = 0; u < n; ++u)
        edg[u][u] = 1;
    for (int u = 0; u < n; ++u) {
        bool isok = true;
        for (int v = 0; v < n; ++v) {
            isok &= used[0][u][v];
            //isok &= used[u][v] <= 0;
        }
        if (isok)
            return C = u;
    }
    return -1; 
}

int nextMove(int R) {
    pR = R;
    for (int nC = edg[C]._Find_first(); nC < n; nC = edg[C]._Find_next(nC)) { 
        if (depth[1][nC][R] < depth[0][C][R]) {
            return C = nC;
        }
    }
    assert(0);
}

Compilation message (stderr)

coprobber.cpp: In function 'int start(int, bool (*)[500])':
coprobber.cpp:20:9: warning: variable 'deg' set but not used [-Wunused-but-set-variable]
   20 |     int deg[MAX_N];
      |         ^~~

• Subtask 1: 16 / 16
• Subtask 2: 14 / 14
• Subtask 3: 30 / 30
• Subtask 4: 40 / 40