Submission #378948

#	Time	Username	Problem	Language	Result	Execution time	Memory
378948		dannyboy20031204	Evacuation plan (IZhO18_plan)	C++17	100 / 100	3374 ms	38496 KiB

plan

#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define z return 0;
using namespace std;
const int N = 1e5 + 5, inf = 1e9 + 1; //
int p[N];
int get(int pos){
    return p[pos] = p[pos] == pos ? pos : get(p[pos]);
}
void merge(int a, int b){
    a = get(a), b = get(b);
    p[a] = b;
}
void init(){
    for (int i = 0; i < N; i++) p[i] = i;
}
int main(){
    ios::sync_with_stdio(0), cin.tie(0);
    int n, m, k, t;
    cin >> n >> m;
    vector<pair<int, int>> g[n + 1], ord;
    for (int i = 0; i < m; i++){
        int u, v, w;
        cin >> u >> v >> w;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    cin >> k;
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
    int dis[n + 1];
    for (int &i : dis) i = inf;
    for (int i = 0, u; i < k; i++){
        cin >> u;
        q.push({0, u});
    }
    while (!q.empty()){
        auto u = q.top();
        q.pop();
        if (u.fi >= dis[u.se]) continue;
        ord.push_back({u.se, u.fi});
        dis[u.se] = u.fi;
        for (auto i : g[u.se]) q.push({u.fi + i.se, i.fi});
    }
    reverse(ord.begin(), ord.end());
    cin >> t;
    int l[t], r[t], st[t], ed[t];
    for (int i = 0; i < t; i++){
        cin >> st[i] >> ed[i];
        l[i] = 0, r[i] = inf;
    }
    for (int _ = 0; _ < 31; _++){
        init();
        vector<pair<int, int>> vv;
        for (int i = 0; i < t; i++){
            int mid = l[i] + r[i] >> 1;
            vv.push_back({mid, i});
        }
        sort(vv.begin(), vv.end(), greater<pair<int, int>>());
        int vis[n + 1]{}, ptr = 0;
        for (auto u : ord){
            while (ptr < t and vv[ptr].fi > u.se){
                int i = vv[ptr].se;
                if (get(st[i]) == get(ed[i])) l[i] = (l[i] + r[i] >> 1) + 1;
                else r[i] = l[i] + r[i] >> 1;
                ptr++;
            }
            for (auto i : g[u.fi]) if (vis[i.fi]) merge(i.fi, u.fi);
            vis[u.fi] = true;
        }
    }
    for (int i = 0; i < t; i++) cout << max(0, l[i] - 1) << '\n';
}

Compilation message (stderr)

plan.cpp: In function 'int main()':
plan.cpp:57:28: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   57 |             int mid = l[i] + r[i] >> 1;
      |                       ~~~~~^~~~~~
plan.cpp:65:60: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   65 |                 if (get(st[i]) == get(ed[i])) l[i] = (l[i] + r[i] >> 1) + 1;
      |                                                       ~~~~~^~~~~~
plan.cpp:66:34: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   66 |                 else r[i] = l[i] + r[i] >> 1;
      |                             ~~~~~^~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46