Submission #83175

#	Time	Username	Problem	Language	Result	Execution time	Memory
83175		RezwanArefin01	Beads and wires (APIO14_beads)	C++17	28 / 100	1079 ms	10112 KiB

beads

///usr/bin/g++ -O2 $0 -o ${0%.cpp} && echo "----------" && ./${0%.cpp}; exit;
#include <bits/stdc++.h>
using namespace std;

typedef long long ll; 

const int N = 2e5 + 10; 
vector<int> adj[N], cost[N]; 
ll dp[N][2]; 

ll f(int u, int par, bool c) {
    if(par && adj[u].size() == 1) {
        if(c) return -1e18; 
        else return 0; 
    }
    ll &ret = dp[u][c]; 
    if(~ret) return ret; 
    ret = 0; 

    ll sum = 0; 
    for(int i = 0; i < adj[u].size(); i++) {
        int v = adj[u][i], c = cost[u][i]; 
        if(v == par) continue; 
        sum += max(f(v, u, 0), f(v, u, 1) + c); 
    }

    if(!c) return ret = sum;

    for(int i = 0; i < adj[u].size(); i++) {
        int v = adj[u][i], c = cost[u][i];
        if(v == par) continue; 
        ll cont = max(f(v, u, 0), f(v, u, 1) + c);
        ret = max(ret, sum - cont + f(v, u, 0) + c); 
    }
    return ret; 
}

int main() {
    int n; scanf("%d", &n);
    for(int i = 1; i < n; i++) {
        int u, v, c;
        scanf("%d %d %d", &u, &v, &c); 
        adj[u].push_back(v); 
        adj[v].push_back(u); 
        cost[u].push_back(c);
        cost[v].push_back(c); 
    }
    ll ans = 0; 
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) 
            dp[j][0] = dp[j][1] = -1; 
        ans = max(ans, f(i, 0, 0)); 
    }
    printf("%lld\n", ans); 
}

Compilation message (stderr)

beads.cpp: In function 'll f(int, int, bool)':
beads.cpp:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < adj[u].size(); i++) {
                    ~~^~~~~~~~~~~~~~~
beads.cpp:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < adj[u].size(); i++) {
                    ~~^~~~~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:39:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     int n; scanf("%d", &n);
            ~~~~~^~~~~~~~~~
beads.cpp:42:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &u, &v, &c); 
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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