Submission #1103907

#	Time	Username	Problem	Language	Result	Execution time	Memory
1103907		Zero_OP	Robot (JOI21_ho_t4)	C++14	100 / 100	800 ms	96392 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#define rep(i, l, r) for(int i = (l), _r = (r); i < _r; ++i)
#define FOR(i, l, r) for(int i = (l), _r = (r); i <= _r; ++i)
#define ROF(i, r, l) for(int i = (r), _l = (l); i >= _l; --i)
#define all(v) begin(v), end(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define sz(v) (int)v.size()
#define dbg(x) "[" #x " = " << (x) << "]"

template<typename T>
bool minimize(T& a, const T& b){
    if(a > b) return a = b, true; return false;
}

template<typename T>
bool maximize(T& a, const T& b){
    if(a < b) return a = b, true; return false;
}

using ll = long long;
using ld = long double;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T> T random_int(T l, T r){ return uniform_int_distribution<T>(l, r)(rng); }
template<typename T> T random_real(T l, T r){ return uniform_real_distribution<T>(l, r)(rng); }

const int MAX = 2e5 + 5;

struct DisjointSet{
    vector<int> lab;
    DisjointSet(int n) : lab(n, -1) {}

    int root(int u){
        return lab[u] < 0 ? u : (lab[u] = root(lab[u]));
    }

    bool unite(int u, int v){
        u = root(u);
        v = root(v);
        if(u == v) return false;
        if(lab[u] > lab[v]) swap(u, v);
        lab[u] += lab[v];
        lab[v] = u;
        return true;
    }

    bool same_set(int u, int v){
        return root(u) == root(v);
    }
};

int n, m;
map<int, vector<pair<int, int>>> adj[MAX];
map<int, ll> same_color_sum[MAX];
ll dp[MAX];
map<int, ll> dp_last[MAX];


void testcase(){
    cin >> n >> m;
    DisjointSet dsu(n + 1);
    while(m--){
        int u, v, c, p;
        cin >> u >> v >> c >> p;
        dsu.unite(u, v);
        adj[u][c].push_back({v, p});
        adj[v][c].push_back({u, p});
        same_color_sum[u][c] += p;
        same_color_sum[v][c] += p;
//        cout << u << " " << c << " " << p << '\n';
//        cout << v << " " << c << " " << p << '\n';

    }

    if(!dsu.same_set(1, n)){
        cout << -1 << '\n';
        return;
    }

    memset(dp, 0x3f, sizeof(dp));
    priority_queue<tuple<ll, int, int>> pq;
    pq.push({-(dp[1] = 0), 1, 0});

    while(!pq.empty()){
        ll mincost; int u, c;
        tie(mincost, u, c) = pq.top(); pq.pop();

        mincost *= -1;

//        cout << dbg(u) << dbg(c) << dbg(mincost) << '\n';

        if(c == 0){
            if(mincost != dp[u]) continue;
            //last edge color does not matter
            for(auto [c, vec] : adj[u]){
                ll tot = same_color_sum[u][c];
                for(auto [v, w] : vec){

                    ll change_neighbours = dp[u] + tot - w;
                    if(minimize(dp[v], change_neighbours)){
//                        cout << dbg(v) << dbg(change_neighbours) << '\n';
                        pq.push({-dp[v], v, 0}); //we can consider this edge as color 0 because it never goes back same edge
                    }

                    ll change_current = dp[u] + w;
                    if(minimize(dp[v], change_current)){
//                        cout << dbg(v) << dbg(change_current) << '\n';
                        pq.push({-dp[v], v, 0}); //as same as above
                    }

                    ll keep = dp[u];
                    if(dp_last[v].find(c) == dp_last[v].end() || dp_last[v][c] >  keep){

                        dp_last[v][c] = keep;
                        pq.push({-keep, v, c});
                    }
                }
            }
        } else{
            ll correct = dp_last[u][c];
            if(mincost != correct) continue;

            ll tot = same_color_sum[u][c];
            for(auto [v, w] : adj[u][c]){
                ll change_neighbours = mincost + tot - w;
                if(minimize(dp[v], change_neighbours)){
                    pq.push({-dp[v], v, 0}); //consider same cases
                }
            }
        }
    }

    ll ans = dp[n];

    cout << ans << '\n';
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    #define filename "task"
    if(fopen(filename".inp", "r")){
        freopen(filename".inp", "r", stdin);
        freopen(filename".out", "w", stdout);
    }

    int T = 1; //cin >> T;
    while(T--) testcase();

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'bool minimize(T&, const T&)':
Main.cpp:15:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   15 |     if(a > b) return a = b, true; return false;
      |     ^~
Main.cpp:15:35: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   15 |     if(a > b) return a = b, true; return false;
      |                                   ^~~~~~
Main.cpp: In function 'bool maximize(T&, const T&)':
Main.cpp:20:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   20 |     if(a < b) return a = b, true; return false;
      |     ^~
Main.cpp:20:35: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   20 |     if(a < b) return a = b, true; return false;
      |                                   ^~~~~~
Main.cpp: In function 'void testcase()':
Main.cpp:98:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   98 |             for(auto [c, vec] : adj[u]){
      |                      ^
Main.cpp:100:26: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  100 |                 for(auto [v, w] : vec){
      |                          ^
Main.cpp:127:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  127 |             for(auto [v, w] : adj[u][c]){
      |                      ^
Main.cpp: In function 'int main()':
Main.cpp:147:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  147 |         freopen(filename".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:148:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  148 |         freopen(filename".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 34 / 34
• Subtask 2: 24 / 24
• Subtask 3: 42 / 42