Submission #1037314

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037314		onbert	Friend (IOI14_friend)	C++17	27 / 100	2 ms	6492 KiB

friend

#include "friend.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
int n, a[maxn], t[maxn];
vector<int> adj[maxn][2];

int dp[maxn][3];
void dfs(int u) {
    for (int i=0;i<=1;i++) for (int v:adj[u][i]) dfs(v);
    int pt = 0, cur = 0;
    for (int v:adj[u][0]) cur += dp[v][2];
    for (int v:adj[u][1]) cur += dp[v][0];
    dp[u][0] = cur;
    for (int v:adj[u][0]) {
        while (pt<adj[u][1].size() && adj[u][1][pt] < v) cur += dp[adj[u][1][pt]][1] - dp[adj[u][1][pt]][0], pt++;
        dp[u][0] = max(cur, dp[u][0]);
        cur += dp[v][0] - dp[v][1];
        // if (u==0) cout << cur << endl;
    }
    while (pt<adj[u][1].size()) cur += dp[adj[u][1][pt]][1] - dp[adj[u][1][pt]][0], pt++;
    dp[u][0] = max(cur, dp[u][0]);

    dp[u][1] = 0;
    for (int v:adj[u][0]) dp[u][1] += dp[v][2];
    for (int v:adj[u][1]) dp[u][1] += dp[v][0];
    
    dp[u][2] = a[u];
    for (int v:adj[u][0]) dp[u][2] += dp[v][1];
    for (int v:adj[u][1]) dp[u][2] += dp[v][2];
    dp[u][2] = max(dp[u][0], dp[u][2]);
}

int findSample(int N, int confidence[], int host[], int protocol[]){
	n = N;
    for (int i=0;i<n;i++) a[i] = confidence[i];
    t[0] = 0;
    for (int i=1;i<n;i++) t[i] = protocol[i];
    for (int i=1;i<n;i++) adj[host[i]][t[i]].push_back(i);
    dfs(0);
    // for (int j=0;j<=1;j++) {
        // cout << j << endl;
        // for (int i=0;i<n;i++) cout << dp[i][j] << " "; cout << endl;
    // }
    return max(dp[0][1], dp[0][2]);
}

Compilation message (stderr)

friend.cpp: In function 'void dfs(int)':
friend.cpp:16:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |         while (pt<adj[u][1].size() && adj[u][1][pt] < v) cur += dp[adj[u][1][pt]][1] - dp[adj[u][1][pt]][0], pt++;
      |                ~~^~~~~~~~~~~~~~~~~
friend.cpp:21:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |     while (pt<adj[u][1].size()) cur += dp[adj[u][1][pt]][1] - dp[adj[u][1][pt]][0], pt++;
      |            ~~^~~~~~~~~~~~~~~~~

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