Submission #97942

#	Time	Username	Problem	Language	Result	Execution time	Memory
97942		SpeedOfMagic	Cop and Robber (BOI14_coprobber)	C++17	60 / 100	1598 ms	226056 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];
vector<int> g2[M], rev2[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;
}
 
char vis[M];
int good[M];
int d[M];

void expand(int cur) {
	if (g2[cur].size() == 0) {
		good[cur] = -2;
	} else {
		for (int i : g2[cur]) {
			if (good[i] == -1 && cur / (maxN * maxN))
				return;
			else if (good[i] != -1 && cur / (maxN * maxN) == 0) {
				good[cur] = i;
				break;
			}
		}
		if (good[cur] == -1 && good[g2[cur][0]] != -1)
			good[cur] = g2[cur][0];
	}
	
	if (good[cur] != -1) {
		for (int i : rev2[cur])
			if (good[i] == -1)
				expand(i);
	}
}

void add(int v, int u) {
	g2[v].push_back(u);
	rev2[u].push_back(v);
}
 
int loc;
int start(int N, bool A[MAX_N][MAX_N]) {
	memset(good, -1, sizeof good);
	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) {
				add(enc(i, j, 0), enc(i, j, 1));
				for (int k : g[i])
					add(enc(i, j, 0), enc(k, j, 1));
				for (int k : g[j])
					add(enc(i, j, 1), enc(i, k, 0));
			}
	
	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;
}

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