Submission #708078

#	Time	Username	Problem	Language	Result	Execution time	Memory
708078		cig32	Training (IOI07_training)	C++17	0 / 100	2 ms	596 KiB

training

#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
  if(p==0) return 1 % MOD;
  int r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
int inv(int b) { 
  return bm(b, MOD-2);
}
int fastlog(int x) {
  return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }

void solve(int tc) {
  int n, m;
  cin >> n >> m;
  vector<int> chain[n+1];
  vector<pair<int,int> > adj[n+1];
  int tcost = 0;
  for(int i=0; i<m; i++) {
    int a, b, c;
    cin >> a >> b >> c;
    tcost += c;
    if(c == 0) {
      chain[a].push_back(b);
      chain[b].push_back(a);
    }
    else {
      adj[a].push_back({b, c});
      adj[b].push_back({a, c});
    }
  }
  vector<int> ord;
  int st;
  for(int i=1; i<=n; i++) if(chain[i].size() == 1) st = i;
  ord.push_back(st);
  bool vis[n+1];
  for(int i=1; i<=n; i++) vis[i] = 0;
  for(int i=1; i<n; i++) {
    vis[st] = 1;
    for(int x: chain[st]) {
      if(!vis[x]) {
        st = x; break;
      }
    }
    ord.push_back(st);
  }
  int dp[n+1];
  for(int i=1; i<=n; i++) dp[i] = vis[i] = 0;
  int ma = 0;
  for(int x: ord) {
    vis[x] = 1;
    for(pair<int, int> y: adj[x]) {
      if(vis[y.first]) dp[x] = max(dp[x], dp[y.first] + y.second);
    }
    ma = max(ma, dp[x]);
    dp[x] = ma;
  }
  cout << tcost - dp[n] << '\n';
}

int32_t main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
/*
5 8
3 2 0
4 3 0
5 4 0
1 5 0
2 4 2
4 1 2
3 5 5
3 1 1
*/

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 7
• Subtask 5: 0 / 9
• Subtask 6: 0 / 9
• Subtask 7: 0 / 9
• Subtask 8: 0 / 9
• Subtask 9: 0 / 9
• Subtask 10: 0 / 9
• Subtask 11: 0 / 9