제출 #114384

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
114384		E869120	친구 (IOI14_friend)	C++14	46 / 100	33 ms	5212 KiB

friend

#include "friend.h"
#include <bits/stdc++.h>
using namespace std;

vector<int> G[100009];
int dp[100009][2], A[100009];

void dfs(int pos) {
	int m1 = 0, m2 = 0;
	for (int i = 0; i < G[pos].size(); i++) {
		dfs(G[pos][i]);
		m1 += max(dp[G[pos][i]][0], dp[G[pos][i]][1]);
		m2 += dp[G[pos][i]][1];
	}
	m2 += A[pos];
	dp[pos][0] = m2; dp[pos][1] = m1;
}

// Find out best sample
int findSample(int n,int confidence[],int host[],int protocol[]){
	int bit = 0;
	for (int i = 1; i <= n - 1; i++) bit |= (1 << protocol[i]);
	
	if (bit == 1) {
		// Subtask 4.
		for (int i = 0; i < n; i++) A[i] = confidence[i];
		for (int i = 1; i <= n - 1; i++) G[host[i]].push_back(i);
		dfs(0);
		return max(dp[0][0], dp[0][1]);
	}
	if (bit == 2) {
		// Subtask 2.
		int sum = 0; for (int i = 0; i < n; i++) sum += confidence[i];
		return sum;
	}
	if (bit == 4) {
		// Subtask 3.
		int sum = 0; for (int i = 0; i < n; i++) sum = max(sum, confidence[i]);
		return sum;
	}
	if (n <= 10) {
		// Subtask 1.
		for (int i = 1; i <= n - 1; i++) {
			if (protocol[i] == 0 || protocol[i] == 2) {
				G[host[i]].push_back(i);
				G[i].push_back(host[i]);
			}
			if (protocol[i] == 1 || protocol[i] == 2) {
				for (int pos : G[host[i]]) {
					if (pos == i) continue;
					G[pos].push_back(i);
					G[i].push_back(pos);
				}
			}
		}
		int ans = 0;
		for (int i = 0; i < (1 << n); i++) {
			bool flag = false; int sum = 0;
			int bit[10]; for (int j = 0; j < n; j++) { bit[j] = (i / (1 << j)) % 2; sum += bit[j] * confidence[j]; }
			for (int j = 0; j < n; j++) {
				for (int k = 0; k < G[j].size(); k++) { if (bit[j] == 1 && bit[G[j][k]] == 1) flag = true; }
			}
			if (flag == false) ans = max(ans, sum);
		}
		return ans;
	}
	return -1;
}

컴파일 시 표준 에러 (stderr) 메시지

friend.cpp: In function 'void dfs(int)':
friend.cpp:10:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < G[pos].size(); i++) {
                  ~~^~~~~~~~~~~~~~~
friend.cpp: In function 'int findSample(int, int*, int*, int*)':
friend.cpp:61:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int k = 0; k < G[j].size(); k++) { if (bit[j] == 1 && bit[G[j][k]] == 1) flag = true; }
                     ~~^~~~~~~~~~~~~

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