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Submission #20405

# Submission time Handle Problem Language Result Execution time Memory
20405 2017-02-11T04:55:49 Z Namnamseo Beads and wires (APIO14_beads) C++14
57 / 100
 1000 ms 85240 KB 
#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pp;
typedef long long ll;
#define all(x) (x).begin(),(x).end()
#define pb push_back
void read(int& x){ scanf("%d",&x); }
template<typename T,typename... Args> void read(T& a,Args&... b){ read(a); read(b...); }

const int max_n = 200010;
const ll inf = 1LL<<60;

vector<pp> edge[max_n];
map<pp, int> ed;
int par[max_n];

ll   dp [max_n][3][2];
bool chk[max_n][3][2];

int n;

void in(){
	read(n);
	for(int i=1; i<n; ++i){
		int x, y, d; read(x, y, d);
		edge[x].pb({y, d});
		edge[y].pb({x, d});
		ed[{x, y}] = d;
		ed[{y, x}] = d;
	}
}

vector<int> nin[max_n];
ll osum[max_n];
multiset<ll> mev[max_n];

void dfs(int x){
	for(pp tmp:edge[x]){
		int y=tmp.first;
		if(par[x]!=y) par[y]=x, nin[x].pb(y), dfs(y);
	}
	if(par[x]) nin[x].pb(par[x]);
}

ll f(int, int, int);

int vc[max_n];
int lf[max_n];
int ld[max_n];

void fill_val(int p, int from){
	if(lf[p] == from) return;
	if(vc[p] == 0){
		for(pp tmp:edge[p]){
			int x, dst;
			tie(x, dst)=tmp;
			if(x == from){
				ld[p]=dst;
				continue;
			}
			ll ov = max(f(x, p, 0), dst + f(x, p, 1));
			osum[p] += ov;
			mev[p].insert(dst + f(x, p, 0) - ov);
		}
	} else {
		if(lf[p] != -1){
			int x=lf[p], dst=ld[p];
			ll ov = max(f(x, p, 0), dst + f(x, p, 1));
			osum[p] += ov;
			mev[p].insert(dst + f(x, p, 0) - ov);
		}
		if(from != -1){
			int x=from, dst=ed[pp{from, p}];
			ll ov = max(f(x, p, 0), dst + f(x, p, 1));
			osum[p] -= ov;
			mev[p].erase(mev[p].find(dst + f(x, p, 0) - ov));
			ld[p]=dst;
		}
	}
	++vc[p];
	lf[p]=from;
}

ll f(int p, int from, int parity){
	int child=(from == -1) ? p : (par[from]==p ? from:p);
	int sec = (from == -1) ? 2 : (p==child);
	ll& mydp = dp[child][sec][parity];
	if(chk[child][sec][parity]) return mydp;
	chk[child][sec][parity]=1;
	mydp = -inf;
    
	fill_val(p, from);
	if(parity == 0){
		mydp = osum[p];
	} else {
		if(mev[p].size())
			mydp = osum[p] + *--mev[p].end();
	}
	
	return mydp;
}

int main()
{
	in(); dfs(1);
	ll ans = 0;
	for(int i=1; i<=n; ++i){
		multiset<ll> diff;
		for(auto tmp:edge[i]){
			int y, d; tie(y, d) = tmp;
			ll v = d+f(y, i, 0);
			v -= max(f(y, i, 0), d+f(y, i, 1));
			diff.insert(v);
			if(diff.size() == 3u) diff.erase(diff.begin());
		}
		ll mv = f(i, -1, 0);
		ans = max(ans, mv);
		if(diff.size() >= 2u){
			auto it=diff.rbegin();
			auto i2=it; ++i2;
			ans = max(ans, mv + *it + *i2);
		}
	}
	printf("%lld\n", ans);
	return 0;
}

Compilation message

beads.cpp: In function 'void read(int&)':
beads.cpp:7:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void read(int& x){ scanf("%d",&x); }
                    ~~~~~^~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 19092 KB Output is correct
2 Correct 24 ms 19192 KB Output is correct
3 Correct 17 ms 19200 KB Output is correct
4 Correct 18 ms 19172 KB Output is correct
5 Correct 18 ms 19200 KB Output is correct
6 Correct 19 ms 19200 KB Output is correct
7 Correct 18 ms 19172 KB Output is correct
8 Correct 18 ms 19200 KB Output is correct
9 Correct 18 ms 19200 KB Output is correct
10 Correct 17 ms 19200 KB Output is correct
11 Correct 18 ms 19136 KB Output is correct
12 Correct 18 ms 19080 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 19092 KB Output is correct
2 Correct 24 ms 19192 KB Output is correct
3 Correct 17 ms 19200 KB Output is correct
4 Correct 18 ms 19172 KB Output is correct
5 Correct 18 ms 19200 KB Output is correct
6 Correct 19 ms 19200 KB Output is correct
7 Correct 18 ms 19172 KB Output is correct
8 Correct 18 ms 19200 KB Output is correct
9 Correct 18 ms 19200 KB Output is correct
10 Correct 17 ms 19200 KB Output is correct
11 Correct 18 ms 19136 KB Output is correct
12 Correct 18 ms 19080 KB Output is correct
13 Correct 18 ms 19200 KB Output is correct
14 Correct 20 ms 19120 KB Output is correct
15 Correct 19 ms 19140 KB Output is correct
16 Correct 21 ms 19216 KB Output is correct
17 Correct 19 ms 19200 KB Output is correct
18 Correct 18 ms 19200 KB Output is correct
19 Correct 19 ms 19184 KB Output is correct
20 Correct 18 ms 19200 KB Output is correct
21 Correct 18 ms 19328 KB Output is correct
22 Correct 17 ms 19200 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 19092 KB Output is correct
2 Correct 24 ms 19192 KB Output is correct
3 Correct 17 ms 19200 KB Output is correct
4 Correct 18 ms 19172 KB Output is correct
5 Correct 18 ms 19200 KB Output is correct
6 Correct 19 ms 19200 KB Output is correct
7 Correct 18 ms 19172 KB Output is correct
8 Correct 18 ms 19200 KB Output is correct
9 Correct 18 ms 19200 KB Output is correct
10 Correct 17 ms 19200 KB Output is correct
11 Correct 18 ms 19136 KB Output is correct
12 Correct 18 ms 19080 KB Output is correct
13 Correct 18 ms 19200 KB Output is correct
14 Correct 20 ms 19120 KB Output is correct
15 Correct 19 ms 19140 KB Output is correct
16 Correct 21 ms 19216 KB Output is correct
17 Correct 19 ms 19200 KB Output is correct
18 Correct 18 ms 19200 KB Output is correct
19 Correct 19 ms 19184 KB Output is correct
20 Correct 18 ms 19200 KB Output is correct
21 Correct 18 ms 19328 KB Output is correct
22 Correct 17 ms 19200 KB Output is correct
23 Correct 29 ms 20920 KB Output is correct
24 Correct 32 ms 20964 KB Output is correct
25 Correct 32 ms 20952 KB Output is correct
26 Correct 49 ms 22664 KB Output is correct
27 Correct 47 ms 22648 KB Output is correct
28 Correct 50 ms 22832 KB Output is correct
29 Correct 53 ms 22776 KB Output is correct
30 Correct 54 ms 22904 KB Output is correct
31 Correct 48 ms 23544 KB Output is correct

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 19092 KB Output is correct
2 Correct 24 ms 19192 KB Output is correct
3 Correct 17 ms 19200 KB Output is correct
4 Correct 18 ms 19172 KB Output is correct
5 Correct 18 ms 19200 KB Output is correct
6 Correct 19 ms 19200 KB Output is correct
7 Correct 18 ms 19172 KB Output is correct
8 Correct 18 ms 19200 KB Output is correct
9 Correct 18 ms 19200 KB Output is correct
10 Correct 17 ms 19200 KB Output is correct
11 Correct 18 ms 19136 KB Output is correct
12 Correct 18 ms 19080 KB Output is correct
13 Correct 18 ms 19200 KB Output is correct
14 Correct 20 ms 19120 KB Output is correct
15 Correct 19 ms 19140 KB Output is correct
16 Correct 21 ms 19216 KB Output is correct
17 Correct 19 ms 19200 KB Output is correct
18 Correct 18 ms 19200 KB Output is correct
19 Correct 19 ms 19184 KB Output is correct
20 Correct 18 ms 19200 KB Output is correct
21 Correct 18 ms 19328 KB Output is correct
22 Correct 17 ms 19200 KB Output is correct
23 Correct 29 ms 20920 KB Output is correct
24 Correct 32 ms 20964 KB Output is correct
25 Correct 32 ms 20952 KB Output is correct
26 Correct 49 ms 22664 KB Output is correct
27 Correct 47 ms 22648 KB Output is correct
28 Correct 50 ms 22832 KB Output is correct
29 Correct 53 ms 22776 KB Output is correct
30 Correct 54 ms 22904 KB Output is correct
31 Correct 48 ms 23544 KB Output is correct
32 Correct 296 ms 36832 KB Output is correct
33 Correct 287 ms 36860 KB Output is correct
34 Correct 271 ms 37004 KB Output is correct
35 Execution timed out 1083 ms 85240 KB Time limit exceeded
36 Halted 0 ms 0 KB -