Submission #97950

#	Time	Username	Problem	Language	Result	Execution time	Memory
97950		SpeedOfMagic	Cop and Robber (BOI14_coprobber)	C++17	16 / 100	76 ms	9832 KiB

coprobber

#include "coprobber.h"
#include <bits/stdc++.h>
using namespace std;
 
const int maxN = 500;
const int M = 2 * maxN * maxN;
vector<int> g[maxN];

int good[M];
unsigned int d[M];
int siz[M];
int pos[M];

//0 if it's officer's turn, 1 if robber's one
int enc(int officerPos, int robberPos, int whoseTurn) {
	return whoseTurn * maxN * maxN + officerPos * maxN + robberPos;
}

inline void expand(int cur) {
	if (d[cur] == siz[cur] || (cur / (maxN * maxN) == 0 && d[cur])) 
		good[cur] = pos[cur];
	
	if (good[cur] != -1) {
		int officerPos = cur % (maxN * maxN) / maxN;
		int robberPos = cur % maxN;
		if (cur / (maxN * maxN)) { //robber's turn
			int j = enc(officerPos, robberPos, 0);
			if (good[j] == -1) {
				d[j]++;
				pos[j] = cur;
				expand(j);
			}
			for (int i : g[officerPos]) {
				j = enc(i, robberPos, 0);
				if (good[j] == -1) {
					d[j]++;
					pos[j] = cur;
					expand(j);
				}
			}
		} else { //officer's turn
			for (int i : g[robberPos]) {
				int j = enc(officerPos, i, 1);
				if (good[j] == -1) {
					d[j]++;
					pos[j] = cur;
					expand(j);
				}
			}
		}
	}
}
 
int loc;
int start(int N, bool A[MAX_N][MAX_N]) {
	memset(siz, 0, sizeof siz);
	for (int i = 0; i < M; i++)
		pos[i] = -2;
	memset(good, -1, sizeof good);
	memset(d, 0, sizeof d);
	for (int i = 0; i < N; i++)
		for (int j = 0; j < N; j++)
			if (A[i][j]) 
				g[i].push_back(j);
	
	for (int i = 0; i < N; i++)
		for (int j = 0; j < N; j++) 
			if (i != j) {
				siz[enc(i, j, 0)]++;
				siz[enc(i, j, 0)] += g[i].size();
				siz[enc(i, j, 1)] += g[j].size();
			}
	
	for (int i = 0; i < N; i++) {
		expand(enc(i, i, 0));
		expand(enc(i, i, 1));
	}		
			
	for (int i = 0; i < N; i++) {
		bool no = 0;
		for (int j = 0; j < N; j++)
			no |= good[enc(i, j, 0)] == -1;
		
		if (!no) {
			loc = i;
			return i;
		}
	}
    return -1;
}
 
int nextMove(int R) {
	//cout << loc << " " << R << endl;
	loc = good[enc(loc, R, 0)] % (maxN * maxN) / maxN;
	return loc;
}

Compilation message (stderr)

coprobber.cpp: In function 'void expand(int)':
coprobber.cpp:20:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if (d[cur] == siz[cur] || (cur / (maxN * maxN) == 0 && d[cur])) 
      ~~~~~~~^~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 0 / 14
• Subtask 3: 0 / 30
• Subtask 4: 0 / 40