Submission #382073

#	Time	Username	Problem	Language	Result	Execution time	Memory
382073		rocks03	Toll (BOI17_toll)	C++14	25 / 100	3078 ms	9192 KiB

toll

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << ": " << x << " "
#define nl cout << "\n"
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int INF = 1e18;
const int MAXN = 5e4+100;
int K, N, M, Q;
vector<pii> g[MAXN];

vector<int> toposort;
bool vis[MAXN];
void dfs(int v){
    vis[v] = true;
    for(auto [u, w] : g[v]){
        if(!vis[u])
            dfs(u);
    }
    toposort.pb(v);
}

void solve(){
    cin >> K >> N >> M >> Q;
    rep(m, 0, M){
        int a, b, t;
        cin >> a >> b >> t;
        g[a].pb({b, t}); 
    }
    rep(i, 0, N){
        if(!vis[i])
            dfs(i);
    }
    reverse(all(toposort));
    vector<ll> dp0(N, INF);
    dp0[0] = 0;
    for(int v : toposort){
        for(auto [u, w] : g[v]){
            dp0[u] = min(dp0[u], dp0[v] + w);
        }
    }
    vector<ll> k1(N, INF);
    vector<int> comp(N, -1);
    int szcomp = 0;
    for(int v : toposort){
        if(comp[v] == -1){
            comp[v] = szcomp++;
            k1[v] = 0;
        }
        for(auto [u, w] : g[v]){
            comp[u] = comp[v];
            k1[u] = k1[v] + w;
        }
    }
    rep(q, 0, Q){
        int a, b;
        cin >> a >> b;
        if(K == 1){
            if(comp[a] == comp[b] && k1[a] <= k1[b])
                cout << k1[b] - k1[a] << "\n";
            else
                cout << "-1\n";
            continue;
        }
        if(a == 0){
            if(dp0[b] == INF)
                cout << "-1\n";
            else
                cout << dp0[b] << "\n";
        } else{
            vector<ll> dp(N, INF);
            dp[a] = 0;
            for(int v : toposort){
                if(v == b) break;
                for(auto [u, w] : g[v]){
                    dp[u] = min(dp[u], dp[v] + w);
                }
            }
            if(dp[b] == INF)
                cout << "-1\n";
            else
                cout << dp[b] << "\n";
        }
    }
}

int main(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr);
    solve();
    return 0;
}

Compilation message (stderr)

toll.cpp:17:17: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   17 | const int INF = 1e18;
      |                 ^~~~
toll.cpp: In function 'void dfs(int)':
toll.cpp:26:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   26 |     for(auto [u, w] : g[v]){
      |              ^
toll.cpp: In function 'void solve()':
toll.cpp:48:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   48 |         for(auto [u, w] : g[v]){
      |                  ^
toll.cpp:60:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   60 |         for(auto [u, w] : g[v]){
      |                  ^
toll.cpp:85:26: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   85 |                 for(auto [u, w] : g[v]){
      |                          ^

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 0 / 31
• Subtask 5: 0 / 44