Submission #40540

#	Time	Username	Problem	Language	Result	Execution time	Memory
40540		mohammad_kilani	Beads and wires (APIO14_beads)	C++14	13 / 100	7 ms	5120 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] , cnt = 0;
         
        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 && cnt < 100;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;
         
                    }
                    cnt++;
                    ans = max(ans,dp[node][1]);
                }
            }
            printf("%d\n",ans);
            return 0;
        }

Compilation message (stderr)

beads.cpp: In function 'int main()':
beads.cpp:31:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                         for(i=0;i<g[curnode].size();i++){
                                 ~^~~~~~~~~~~~~~~~~~
beads.cpp:11:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d",&n);
             ~~~~~^~~~~~~~~
beads.cpp:14:22: 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:45:51: warning: 'w' may be used uninitialized in this function [-Wmaybe-uninitialized]
                         dp[curnode][0] = sum + mx + w;
                                          ~~~~~~~~~^~~

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