Submission #948529

#	Time	Username	Problem	Language	Result	Execution time	Memory
948529		phone64bit	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	119 ms	25156 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define ll long long

const int mxN = 1e5+10;

struct Q {
    int src; ll w;
    bool operator < (const Q&rhs) const {
        return w>rhs.w;
    }
};

struct path {
    int dest; ll w;
};

struct edge {
    int u, v;
};

vector<edge> k_path, tmp_path;
vector<path> edges[mxN];
bitset<mxN> vs;
ll dp[mxN], k_dp[mxN], ans = 1e18;
int n,m,s,t,u,v; 
priority_queue<Q> pq;

void dfs(int u) {
    vs[u]=1;
    if(u==t&&k_path.size()<tmp_path.size()) {
        k_path = tmp_path;
        return;
    }
    for(auto v: edges[u]) if(!vs[v.dest]) vs[v.dest]=1, tmp_path.push_back({u, v.dest}), dfs(v.dest), tmp_path.pop_back();
}

int main() {
    for(int i=0; i<mxN; i++) dp[i]=1e18;
    scanf("%d%d%d%d%d%d", &n,&m,&s,&t,&u,&v);
    while(m--) {
        int u, v; ll w; scanf("%d%d%lld", &u, &v, &w);
        edges[u].push_back({v, w});
        edges[v].push_back({u, w});
    }
    dfs(s);
    for(auto x: k_path) edges[x.u].push_back({x.v, 0}), edges[x.v].push_back({x.u, 0});
    dp[u] = 0;
    pq.push({u, 0});
    while(!pq.empty()) {
        auto [src, w] = pq.top();
        pq.pop();
        if(src==v) {
            ans=w;
            break;
        }
        for(auto v: edges[src]) {
            if(dp[v.dest]>w+v.w) {
                dp[v.dest]=w+v.w;
                pq.push({v.dest, dp[v.dest]});
            }
        }
    }
    printf("%lld", ans);
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:51:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   51 |         auto [src, w] = pq.top();
      |              ^
commuter_pass.cpp:40:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |     scanf("%d%d%d%d%d%d", &n,&m,&s,&t,&u,&v);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:42:30: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         int u, v; ll w; scanf("%d%d%lld", &u, &v, &w);
      |                         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 16
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45