# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1040689 | Ausp3x | Friend (IOI14_friend) | C++17 | 99 ms | 65536 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
// 人外有人,天外有天
// author: Ausp3x
#pragma GCC optimize("O1, O2, O3, Ofast, unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include "friend.h"
using namespace std;
using namespace __gnu_pbds;
#define fi first
#define se second
#define pb push_back
// #define DEBUG
typedef long long lng;
int const INF32 = 0x3f3f3f3f;
lng const INF64 = 0x3f3f3f3f3f3f3f3f;
vector<vector<int>> adjl;
vector<bool> st4_vst;
// including cur, excluding cur
vector<pair<lng, lng>> st4_dp;
lng st4(int cur, int confidence[]) {
if (st4_dp[cur].fi != 0 || st4_dp[cur].se != 0)
return max(st4_dp[cur].fi, st4_dp[cur].se);
st4_vst[cur] = true;
st4_dp[cur].fi += confidence[cur];
for (int nxt : adjl[cur]) {
if (st4_vst[nxt])
continue;
st4(nxt, confidence);
st4_dp[cur].fi += st4_dp[nxt].se;
st4_dp[cur].se += st4_dp[nxt].fi;
}
return max(st4_dp[cur].fi, st4_dp[cur].se);
}
int findSample(int n, int confidence[], int host[], int protocol[]) {
adjl.clear();
adjl.resize(n);
for (int i = 1; i < n; i++) {
switch (protocol[i]) {
case 0: // IAmYourFriend
adjl[host[i]].pb(i);
adjl[i].pb(host[i]);
break;
case 1: // MyFriendsAreYourFriends
for (int j : adjl[host[i]]) {
adjl[j].pb(i);
adjl[i].pb(j);
}
break;
case 2: // WeAreYourFriends
for (int j : adjl[host[i]]) {
adjl[j].pb(i);
adjl[i].pb(j);
}
adjl[host[i]].pb(i);
adjl[i].pb(host[i]);
break;
default:
return -1;
}
}
if (n <= 10) {
lng ans = 0;
for (int msk = 0; msk < (1 << n); msk++) {
vector<bool> vst(n);
for (int i = 0; i < n; i++)
vst[i] = msk & (1 << i);
lng cur = 0;
for (int i = 0; i < n; i++) {
if (!vst[i])
continue;
cur += confidence[i];
for (int j : adjl[i])
if (vst[j])
goto exit;
}
ans = max(ans, cur);
exit:;
}
#ifdef DEBUG
cout << ans << endl;
#endif
#ifndef DEBUG
return ans;
#endif
}
bool isAll0 = true, isAll1 = true, isAll2 = true;
for (int i = 1; i < n; i++) {
isAll0 &= protocol[i] == 0;
isAll1 &= protocol[i] == 1;
isAll2 &= protocol[i] == 2;
}
if (isAll1) {
lng ans = 0;
for (int i = 0; i < n; i++)
ans += confidence[i];
return ans;
}
if (isAll2) {
lng ans = 0;
for (int i = 0; i < n; i++)
ans = max<lng>(ans, confidence[i]);
return ans;
}
if (isAll0) {
st4_vst.clear();
st4_vst.resize(n);
st4_dp.clear();
st4_dp.resize(n, {0, 0});
return st4(0, confidence);
}
return -1;
}
#ifdef DEBUG
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t = 1;
cin >> t;
while (t--) {
int n;
cin >> n;
int confidence[n];
for (int i = 0; i < n; i++)
cin >> confidence[i];
int host[n], protocol[n];
for (int i = 1; i < n; i++)
cin >> host[i] >> protocol[i];
cout << findSample(n, confidence, host, protocol) << endl;
}
return 0;
}
#endif
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