Submission #1274023

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274023		wedonttalkanymore	Robot (JOI21_ho_t4)	C++20	34 / 100	3093 ms	72592 KiB

Main

#include <bits/stdc++.h>
/*
    Brute to win
*/
using namespace std;
using ll = long long;

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 2e5 + 5, inf = 1e18, mod = 1e9 + 7, block = 320, lim = 19;

int n, m;
vector <pii> adj[N];
int c[N], p[N];
int dp1[N]; // xet den u, type = 0/1 la co thay doi toan bo canh cung mau hay ko
map <int, int> dp2[N], pfs[N];

struct item {
    int c, u, type;
    bool operator <(const item &other) const {
        return c > other.c;
    }
};

void dijk() {
    for (int i = 1; i <= n; i++) {
        dp1[i] = inf;
    }
    for (int i = 1; i <= n; i++) {
        for (auto [v, id] : adj[i]) {
            dp2[i][c[id]] = inf;
        }
    }
    dp1[1] = 0;
    priority_queue <item> q;
    q.push({0, 1, 0});
    while(q.size()) {
        auto [val, u, type] = q.top();
        q.pop();
        if (type == 0) {
            if (val > dp1[u]) continue;
            for (auto [v, id] : adj[u]) {
                if (dp1[v] > dp1[u] + p[id]) {
                    dp1[v] = dp1[u] + p[id];
                    q.push({dp1[v], v, 0}); 
                }
                if (dp1[v] > dp1[u] + pfs[u][c[id]] - p[id]) {
                    dp1[v] = dp1[u] + pfs[u][c[id]] - p[id];
                    q.push({dp1[v], v, 0});
                }
                if (dp2[v][c[id]] > dp1[u]) {
                    dp2[v][c[id]] = dp1[u];
                    q.push({dp2[v][c[id]], v, c[id]});
                }
            }
        }
        else {
            for (auto [v, id] : adj[u]) {
                if (c[id] != type) continue;
                if (dp1[v] > dp2[u][type] + pfs[u][c[id]] - p[id]) {
                    dp1[v] = dp2[u][type] + pfs[u][c[id]] - p[id];
                    q.push({dp1[v], v, 0});
                }
            }
        }
    }
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }
    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int u, v;
        cin >> u >> v >> c[i] >> p[i];
        adj[u].emplace_back(v, i);
        adj[v].emplace_back(u, i);
    }
    for (int i = 1; i <= n; i++) {
        for (auto [v, id] : adj[i]) {
            pfs[i][c[id]] += p[id];
        }
    }
    dijk();
    cout << (dp1[n] >= inf ? -1 : dp1[n]);
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
Main.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 34 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42