Submission #809125

#	Time	Username	Problem	Language	Result	Execution time	Memory
809125		idiotcomputer	Valley (BOI19_valley)	C++11	100 / 100	177 ms	53596 KiB

valley

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

const int mxN = 1e5;
const long long int mxV = 1e15;
bool shop[mxN];
int depth[mxN];
int nidx[mxN];
int ssize[mxN];
long long int dp[mxN][18];
int dpidx[mxN][18];
long long int dis[mxN][18];

void setup(int node, int parent, int cnt, int d, vector<vector<pair<int,int>>> &connect){
    nidx[node] = cnt;
    ssize[node] = 1;
    depth[node] = d;
    pair<int,int> next;
    long long int mini = mxV;
    for (int i =0; i < connect[node].size(); i++){
        next = connect[node][i];
        if (next.first == parent){
            continue;
        }
        
        setup(next.first,node,cnt+ssize[node],d+1, connect);
        ssize[node] += ssize[next.first];
        mini = min(mini, dp[next.first][0] + next.second);
    }
    if (shop[node]){
        mini = 0;
    }
    dis[node][0] = 0;
    dpidx[node][0] = node;
    dp[node][0] = mini;
}

void gdp(int node, int parent, int last, vector<vector<pair<int,int>>> &connect){
    if (parent != -1){
        dis[node][1] = last;
        dpidx[node][1] = parent;
        dp[node][1] = min(dp[node][0], dp[parent][0] + last);
    }
    
    for (int i = 2; i < 18; i++){
        if (dpidx[node][i-1] == -1){
            break;
        } 
        dp[node][i] = min(dp[node][i-1], dp[dpidx[node][i-1]][i-1] + dis[node][i-1]);
        dpidx[node][i] = dpidx[dpidx[node][i-1]][i-1];
        dis[node][i] = dis[node][i-1] + dis[dpidx[node][i-1]][i-1];
    }
    
    pair<int,int> next;
    for (int i =0; i < connect[node].size(); i++){
        next = connect[node][i];
        if (next.first == parent){
            continue;
        }
        gdp(next.first,node,next.second,connect);
    }
    return;
}

long long int query(int a, int b){
    if (a == b){
        return dp[a][0];
    }
   // cout << a << " " << b << " lel ";
   /* for (int i = 0; i < 1e8; i++){
        continue;
    }*/
    for (int i = 0; i < 18; i++){
        if ((dpidx[a][i] == -1) || (depth[dpidx[a][i]] < depth[b])){
         //   cout << i << '\n';
            return min(dp[a][i-1], query(dpidx[a][i-1],b) + dis[a][i-1]);
        }
    }
    cout << "UHOH STINKY\n";
    return -1;
}

int main()
{
    for (int i = 0; i < mxN; i++){
        for (int j =0; j < 18; j++){
            dp[i][j] = mxV;
            dpidx[i][j] = -1;
            dis[i][j] = mxV;
        }
    }   
    
    
    memset(shop,0,sizeof(shop));
    
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int n,s,q,e;
    cin >> n >> s >> q >> e;
    e-=1;
    vector<vector<pair<int,int>>> connect(n);
    vector<pair<pair<int,int>,int>> edges(n-1);
    pair<int,int> temp;
    for (int i = 0; i < n-1; i++){
        cin >> edges[i].first.first >> edges[i].first.second >> edges[i].second;
        edges[i].first.first -= 1;
        edges[i].first.second -= 1;
        temp.first = edges[i].first.second;
        temp.second = edges[i].second;
        connect[edges[i].first.first].push_back(temp);
        temp.first = edges[i].first.first;
        connect[edges[i].first.second].push_back(temp);
    }
    int a;
    for (int i = 0; i < s; i++){
        cin >> a;
        a -= 1;
        shop[a] = true;
    }
    
    setup(e,-1,0,0,connect);
    gdp(e,-1,0,connect);
    
    int I,R;
    int cidx;
    for (int i =0; i < 4*1e8; i++){
        continue;
    }
  /*  for (int i =0; i < n; i++){
        cout << i << ": ";
        for (int j = 0; j < 18; j++){
            cout << dp[i][j] << " ";
        }
        cout<< '\n';
    }
    cout << '\n';
    for (int i =0; i < n; i++){
        cout << i << ": ";
        for (int j = 0; j < 18; j++){
            cout << dpidx[i][j] << " ";
        }
        cout<< '\n';
    }
    cout << '\n';
    for (int i =0; i < n; i++){
        cout << i << ": ";
        for (int j = 0; j < 18; j++){
            cout << dis[i][j] << " ";
        }
        cout<< '\n';
    }
    cout << '\n';*/
    for (int i =0; i < q; i++){
        cin >> I >> R;
        I -= 1;
        R -= 1;
        if (depth[edges[I].first.first] > depth[edges[I].first.second]){
            cidx = edges[I].first.first; 
        } else {
            cidx = edges[I].first.second;
        }
       // cout << nidx[cidx] << " " << ssize[cidx] << " " << nidx[R] << '\n';
        if ((nidx[cidx] > nidx[R]) || (nidx[cidx] + ssize[cidx] <= nidx[R])){
            cout << "escaped\n";
            continue;
        }
        long long int res = query(R,cidx);
        if (res == mxV){
            cout << "oo\n";
        } else {
            cout << res << "\n";
        }
    }
    return 0;
}

Compilation message (stderr)

valley.cpp: In function 'void setup(int, int, int, int, std::vector<std::vector<std::pair<int, int> > >&)':
valley.cpp:20:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |     for (int i =0; i < connect[node].size(); i++){
      |                    ~~^~~~~~~~~~~~~~~~~~~~~~
valley.cpp: In function 'void gdp(int, int, int, std::vector<std::vector<std::pair<int, int> > >&)':
valley.cpp:55:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |     for (int i =0; i < connect[node].size(); i++){
      |                    ~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 23 / 23
• Subtask 4: 41 / 41