Submission #36913

#	Time	Username	Problem	Language	Result	Execution time	Memory
36913		mohammad_kilani	Beads and wires (APIO14_beads)	C++14	28 / 100	1084 ms	5504 KiB

beads

    #include <bits/stdc++.h>
    using namespace std;
    #define mod 1000000007
    #define oo 2000000000
    const int N = 200010;
    vector< pair<int,int> > g[N];
    int n , dp[N][2] , q[N], in[N];
     
    int main() {
    	//freopen("in.txt","r",stdin);
    	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(v,w));
    		g[v].push_back(make_pair(u,w));
    	}
    	int ans = 0 , st = 0 , en = 0 , curnode , w , sum = 0 , mx = 0 , i = 0;
    	for(int node=1;node<=n;node++){
    		if(g[node].size() == 1){
    			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:31:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(i=0;i<g[curnode].size();i++){
                 ~^~~~~~~~~~~~~~~~~~
beads.cpp:11:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
      scanf("%d",&n);
      ~~~~~^~~~~~~~~
beads.cpp:14:12: 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:45:35: warning: 'w' may be used uninitialized in this function [-Wmaybe-uninitialized]
         dp[curnode][0] = sum + mx + w;
                          ~~~~~~~~~^~~

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