Submission #232087

#	Time	Username	Problem	Language	Result	Execution time	Memory
232087		anonymous	Friend (IOI14_friend)	C++14	46 / 100	41 ms	4480 KiB

friend

#include "friend.h"
#include <vector>
#include <iostream>
#define MAXN 1005
using namespace std;
// Find out best sample
vector <int> adj[MAXN];
int wt[MAXN], dp[MAXN][2];
bool done[MAXN][2];
int slv(int u, int prev, bool b) {
    if (done[u][b]) {return(dp[u][b]);}
    done[u][b]=true;
    for (int v: adj[u]) {
        if (v == prev) {continue;}
        dp[u][b] += slv(v, u, 1);
    }
    if (b == 1) {
        int v2 = wt[u];
        for (int v: adj[u]) {
            if (v == prev) {continue;}
            v2 += slv(v, u, 0);
        }
        dp[u][b] = max(dp[u][b], v2);
    }
    return(dp[u][b]);
}

//Max matching
int Match[MAXN], vis[MAXN], Num;

bool dfs(int u, int t) {
    vis[u] = t;
    for (int v: adj[u]) {
        if (vis[v] == t) {continue;}
        vis[v] = t;
        if (Match[v] == -1) {
            Match[u] = v, Match[v] = u;
            return(true);
        } else if (vis[Match[v]] != t && dfs(Match[v], t)) {
            Match[u] = v, Match[v] = u;
            return(true);
        }
    }
    return(false);
}

int findSample(int n,int C[],int H[],int P[]){ //confidence, host, protocol
	bool SB1=n <= 12, SB2=true, SB3=true, SB4=true, SB5=true;
    for (int i=1; i<n; i++) {
        if (P[i] != 1) {SB2=false;} //myfriends
        if (P[i] != 2) {SB3 = false;} //ourfriends
        if (P[i] != 0) {SB4 = false;} //Ifriends
        if (P[i] == 2) {SB5 = false;}
    }
    for (int i=1; i<n; i++) {
        if (P[i] == 0) { //I am friend
            adj[i].push_back(H[i]);
            adj[H[i]].push_back(i);
            //printf("%d %d\n",i,H[i]);
        } else if (P[i] == 1) { //My friends
            for (int v: adj[H[i]]) {
                adj[i].push_back(v);
                adj[v].push_back(i);
                //printf("%d %d\n",v,i);
            }
        } else { //everything
            //printf("%d %d\n",i,H[i]);
            for (int v: adj[H[i]]) {
                adj[i].push_back(v);
                adj[v].push_back(i);
                //printf("%d %d\n",v,i);
            }
            adj[i].push_back(H[i]);
            adj[H[i]].push_back(i);
        }
    }
    for (int i=0; i<n; i++) {
        wt[i] = C[i];
    }
    if (SB1) {
        int ans = 0;
        for (int i=0; i<(1<<n); i++) {
            bool ok = true;
            for (int a=0; a<n; a++) {
                for (int b: adj[a]) {
                    if ((i&(1<<a)) && (i&(1<<b))) {
                        ok = false;
                    }
                }
            }
            if (ok) {
                int res = 0;
                for (int j=0; j<n; j++) {
                    if (i&(1<<j)) {res += C[j];}
                }
                ans = max(ans, res);
            }
        }
        return(ans);
    } else if (SB3) { //no edges with myfriends
        int mx = 0;
        for (int i=0; i<n; i++) {
            mx = max(mx, C[i]);
        }
        return(mx);
    } else if (SB2) { //everything connected
        int Sum = 0;
        for (int i=0; i<n; i++) {
            Sum += C[i];
        }
        return(Sum);
    } else if (SB4) {
        return(slv(0,-1,1));
    } else if (SB5) {
        for (int i=0; i<n; i++) {
            Match[i] = -1;
        }
        for (int i=0; i<n; i++) {
            Num += (int) dfs(i, i+1);
        }
        return(n - Num);
    }
}

Compilation message (stderr)

friend.cpp: In function 'int findSample(int, int*, int*, int*)':
friend.cpp:123:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

• Subtask 1: 11 / 11
• Subtask 2: 8 / 8
• Subtask 3: 8 / 8
• Subtask 4: 19 / 19
• Subtask 5: 0 / 23
• Subtask 6: 0 / 31