Submission #348344

#	Time	Username	Problem	Language	Result	Execution time	Memory
348344		parsabahrami	Beads and wires (APIO14_beads)	C++17	100 / 100	216 ms	30556 KiB

beads

// Call my Name and Save me from The Dark
#include <bits/stdc++.h>
 
using namespace std;

typedef long long int ll;
typedef pair<int, ll> pii;
 
#define SZ(x)                       (int) x.size()
#define F                           first
#define S                           second

const int N = 2e5 + 10, MOD = 1e9 + 7;
ll dp[2][2][N], shit[N]; int n;
vector<pii> adj[N];

void DFS(int v, int p = -1) {
    dp[0][0][v] = 0, dp[1][0][v] = dp[0][1][v] = dp[1][1][v] = shit[v] = -MOD;
    for (pii u : adj[v]) {
        if (u.F != p) DFS(u.F, v);
    }
    for (pii u : adj[v]) {
        if (u.F != p) {
            //printf("%d %lld %lld %lld %lld %lld\n", v, dp[0][0][v], dp[0][1][v], dp[1][0][v], dp[1][1][v], shit[v]);
            int x11 = dp[1][1][v], x01 = dp[0][1][v], x10 = dp[1][0][v], x00 = dp[0][0][v], sv = shit[v];
            dp[0][0][v] += max(dp[0][0][u.F], dp[0][1][u.F] + u.S);
            dp[0][1][v] = max(x01 + max(dp[0][0][u.F], dp[0][1][u.F] + u.S), x00 + dp[0][0][u.F] + u.S);
            dp[1][0][v] = max({x00 + max(dp[1][0][u.F], dp[1][1][u.F] + u.S), u.S + x01 + max(dp[0][0][u.F], dp[1][0][u.F]), x10 + max(dp[0][0][u.F], dp[0][1][u.F] + u.S)});
            dp[1][0][v] = max(dp[1][0][v], x11 + u.S + dp[0][0][u.F]);
            dp[1][1][v] = max(u.S + x00 + dp[1][0][u.F], x11 + max(dp[0][0][u.F], dp[0][1][u.F] + u.S));
            shit[v] = max(sv + max(dp[0][0][u.F], dp[0][1][u.F] + u.S), x00 + max(dp[1][0][u.F], dp[1][1][u.F] + u.S));
        }
    }
    //printf("%d %lld %lld %lld %lld %lld\n", v, dp[0][0][v], dp[0][1][v], dp[1][0][v], dp[1][1][v], shit[v]);
}

int main() {
    scanf("%d", &n);
    for (int i = 1; i < n; i++) {
        int u, v; ll w; scanf("%d%d%lld", &u, &v, &w);
        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
    }
    DFS(1);
    printf("%lld\n", max({dp[1][0][1], dp[0][0][1], shit[1]}));
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'int main()':
beads.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   38 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
beads.cpp:40:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   40 |         int u, v; ll w; scanf("%d%d%lld", &u, &v, &w);
      |                         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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