Submission #537623

#	Time	Username	Problem	Language	Result	Execution time	Memory
537623		dantoh000	Paths (RMI21_paths)	C++14	20 / 100	212 ms	17876 KiB

Main

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef pair<int,int> ii;
int n,k;
vector<ii> G[100005];
ll d[100005];
int p[100005][18];
int dep[100005];
int d1 = 0;
int d2 = 0;
int dp[100005];
int vis[19];
ll md = 0;
void dfs(int u){
    for (auto v : G[u]){
        if (v.fi == p[u][0]) continue;
        d[v.fi] = d[u]+v.se;
        dep[v.fi] = dep[u]+1;
        p[v.fi][0] = u;
        dp[v.fi] = v.se;
        dfs(v.fi);
    }
}
int lca(int a, int b){
    if (dep[a] > dep[b]) swap(a,b);
    int DD = dep[b] - dep[a];
    for (int k = 0; k < 18; k++){
        if (DD>>k&1){
            b = p[b][k];
        }
    }
    if (a == b) return a;
    for (int k = 17; k >= 0; k--){
        if (p[a][k] != -1 && p[a][k] != p[b][k]){
            a = p[a][k];
            b = p[b][k];
        }
    }
    assert(p[a][0] == p[b][0]);
    return p[a][0];
}
ll dist(int a, int b){
    return d[a] + d[b] - 2*d[lca(a,b)];
}
int main(){
    scanf("%d%d",&n,&k);
    for (int i = 1 ; i < n; i++){
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c);
        G[a].push_back({b,c});
        G[b].push_back({a,c});
    }
    memset(p,-1,sizeof(p));
    p[1][0] = -1;
    dfs(1);
    for (int k = 1; k < 18; k++){
        for (int i = 1; i <=n ;i ++ ){
            if (p[i][k-1] != -1) p[i][k] = p[p[i][k-1]][k-1];
        }
    }
    if (k == 1){
        for (int i = 1; i <= n; i++){
            if (d1 == 0 || d[d1] < d[i]) d1 = i;
        }
        for (int i = 1; i <= n; i++){
            ll nd = dist(d1, i);
            if (md < nd){
                d2 = i;
                md = nd;
            }
        }
        for (int i = 1; i <= n; i++){
            printf("%lld\n",max(dist(i,d1), dist(i,d2)));
        }
    }
    else{
        for (int i = 1; i <= n; i++){
            d[i] = 0;
            p[i][0] = -1;
            dp[i] = 0;
            dfs(i);
            ll ans = 0;
            for (int mask = 1; mask < (1<<n); mask++){
                if (__builtin_popcount(mask) != k) continue;
                memset(vis,0,sizeof(vis));

                ll sm = 0;
                for (int i = 1; i <= n; i++){
                    if (mask>>(i-1)&1){
                        int cur = i;
                        while (cur != -1 && !vis[cur]){
                            vis[cur] = true;
                            sm += dp[cur];
                            cur = p[cur][0];


                        }
                    }
                }
                ans = max(ans,sm);
            }
            printf("%lld\n",ans);
        }

    }


}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:49:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |     scanf("%d%d",&n,&k);
      |     ~~~~~^~~~~~~~~~~~~~
Main.cpp:52:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         scanf("%d%d%d",&a,&b,&c);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 0 / 11
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 12 / 12
• Subtask 6: 0 / 32