Submission #40538

#	Time	Username	Problem	Language	Result	Execution time	Memory
40538		mohammad_kilani	Beads and wires (APIO14_beads)	C++14	0 / 100	4 ms	2688 KiB

beads

#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define oo 1000000000
const double PI = acos(-1);
const int N = 100010;
vector< pair<int,int> > g[N];
int n , dp[N][2] , q[N], in[N];

int main(){
   scanf("%d",&n);
   for(int i=0;i<n-1;i++){
   	int u , v, w;
   	scanf("%d%d%d",&u,&v,&w);
   	g[u].push_back(make_pair(u,w));
   	g[v].push_back(make_pair(v,w));
   }
   int ans = 0 , st = 0 , en = 0 , curnode , w , sum = 0 , mx = 0 , i = 0 , cnt = 0;
	    	for(int node=1;node<=n && cnt < 100;node++){
	    		if(g[node].size() == 1){
	    			cnt++;
	    			st = 0 , en = 0 ,sum = 0;
	    			for(i=1;i<=n;i++){
	    				in[i] = g[i].size() - (i != node);
	    				if(in[i] == 0)
	    					q[en++] = i;
	    			}
	    			while(st < en){
	    				curnode = q[st++];
	    				dp[curnode][1] = dp[curnode][0] = 0;
	    				sum = 0 , mx = -oo;
	    				for(i=0;i<g[curnode].size();i++){
	    					if(in[g[curnode][i].first] != 0){
	    						w = g[curnode][i].second;
	    						in[g[curnode][i].first]--;
	    						if(in[g[curnode][i].first] == 0){
	    							q[en++] = g[curnode][i].first;
	    						}
	    					}
	    					else{
	    						sum += max(dp[g[curnode][i].first][0],dp[g[curnode][i].first][1]);
	    						mx = max(mx,dp[g[curnode][i].first][1] + g[curnode][i].second - max(dp[g[curnode][i].first][0],dp[g[curnode][i].first][1]));
	    					}
	    				}
	    				dp[curnode][1] = sum;
	    				dp[curnode][0] = sum + mx + w;
	     
	    			}
	    			ans = max(ans,dp[node][1]);
	    		}
	    	}
	    	printf("%d\n",ans);
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'int main()':
beads.cpp:32:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
          for(i=0;i<g[curnode].size();i++){
                  ~^~~~~~~~~~~~~~~~~~
beads.cpp:11:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d",&n);
    ~~~~~^~~~~~~~~
beads.cpp:14:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d",&u,&v,&w);
     ~~~~~^~~~~~~~~~~~~~~~~~~
beads.cpp:46:36: warning: 'w' may be used uninitialized in this function [-Wmaybe-uninitialized]
          dp[curnode][0] = sum + mx + w;
                           ~~~~~~~~~^~~

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