Submission #49469

#	Time	Username	Problem	Language	Result	Execution time	Memory
49469		hamzqq9	Beads and wires (APIO14_beads)	C++14	0 / 100	4 ms	2688 KiB

beads

#include<bits/stdc++.h>
#define lf double
#define ll long long
#define cc pair<char,char>
#define ull unsigned ll
#define ii pair<int,int>
#define li pair<ll,int>
#define iii pair<int,ii>
#define iiii pair<ii,ii>
#define iiii2 pair<int,iii>
#define lii pair<ll,ii>
#define lolo pair<ll,ll>
#define heap priority_queue
#define mp make_pair
#define st first
#define nd second
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define all(x) x.begin(),x.end()
#define len(x) strlen(x)
#define sz(x) (int) x.size()
#define orta ((bas+son)/2)
#define min3(x,y,z) min(min(x,y),z)
#define max3(x,y,z) max(max(x,y),z)
#define umin(x,y) x=min(x,y)
#define umax(x,y) x=max(x,y)
#define dbgs(x) cerr<<(#x)<<" --> "<<(x)<<" "
#define dbg(x) cerr<<(#x)<<" --> "<<(x)<<endl;getchar()
#define MOD 1000000000
#define inf 2000000005
#define N 100005
#define LOG 20
#define magic 100
#define KOK 250
#define EPS 0.0025
#define pw(x) (1<<(x))
#define PI 3.1415926535
using namespace std;

int n,x,y,z;
int dp[N][2];
vector<ii> v[N];
int pre[N];

void dfs(int node,int ata,int ue) {

	for(int i=0;i<sz(v[node]);i++) {

		ii go=v[node][i];

		if(go.st==ata) {

			swap(v[node][i],v[node][sz(v[node])-1]);

			v[node].ppb();

			i--;

			continue ;

		}

		dfs(go.st,node,go.nd);
 
	}

	for(int i=0;i<sz(v[node]);i++) {

		ii go=v[node][i];

		pre[i+1]=pre[i]+dp[go.st][0];

	}

	// make center

	int mx=-inf;

	for(int i=0;i<sz(v[node]);i++) {

		ii go=v[node][i];

		for(int j=0;j<2;j++) {

			umax(dp[node][j],pre[sz(v[node])]-dp[go.st][0]+go.nd+dp[go.st][1]+mx);

		}

		umax(mx,go.nd-dp[go.st][0]+dp[go.st][1]);

	}

	// not blocked

	for(int i=0;i<sz(v[node]);i++) {

		ii go=v[node][i];

		umax(dp[node][0],dp[go.st][1]+go.nd+ue+pre[sz(v[node])]-dp[go.st][0]);

	}

	// no center

	for(int j=0;j<2;j++) {

		umax(dp[node][j],pre[sz(v[node])]);

	}

	//printf("node--> %d zero--> %d one--> %d\n",node,dp[node][0],dp[node][1]);

}

int main() {
 
 	#if 0
	freopen("input.txt","r",stdin);
 	#endif

	scanf("%d",&n);

	for(int i=1;i<n;i++) {

		scanf("%d %d %d",&x,&y,&z);

		v[x].pb({y,z});
		v[y].pb({x,z});

	}

	dfs(1,0,0);

	printf("%d",dp[1][1]);

}

Compilation message (stderr)

beads.cpp: In function 'int main()':
beads.cpp:123:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
beads.cpp:127:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d",&x,&y,&z);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43