Submission #701130

#	Time	Username	Problem	Language	Result	Execution time	Memory
701130		Quan2003	Swapping Cities (APIO20_swap)	C++17	6 / 100	367 ms	47960 KiB

swap

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 3e5 + 100;
const int INF = 1e7 + 10; 
long long n,m,q,dsz,E;
int timer = 1;
vector<int>adj[N + 1];
int fa[N + 1];
bool cyc[N + 1]; 
int up[23][N + 1],dp[N + 1],val[N + 1];
int lf[N + 1],ri[N + 1]; 
int in[N + 1],to[N + 1]; 
struct edge{
     int w,u,v;
} edges[N + 1]; 
int find(int u){
     if(u == fa[u]) return u;
     return fa[u] = find(fa[u]); 
}
void dfs_calc(int u){
    to[timer] = u; 
    in[u] = timer++; 
    for(int i = 1; i < 23 ; i++){
        up[i][u] = up[i - 1][up[i - 1][u]];
    }
    for(int i = 0; i < adj[u].size(); i++){
        int v = adj[u][i]; 
        if(v == up[0][u]) continue;
        dp[v] = dp[up[0][v] = u] + 1;      
        dfs_calc(v);
    }
}
int lca(int a, int b){
    if(dp[a] < dp[b]) swap(a,b);
    int d = dp[a] - dp[b];
    for(int i = 0; i < 23 ; i++){
        if( (d >> i) & 1) a = up[i][a];
    }
    if(a == b) return a;
    for(int i = 22; i >= 0; i--){
         int tA = up[i][a]; int tB = up[i][b];
         if(tA != tB) {
            a = tA; b = tB;
         }
    } 
    return up[0][a];
} 
bool cmp(edge &a, edge &b){
     return a.w < b.w; 
}
void init(int N, int M,std::vector<int> U, std::vector<int> V, std::vector<int> W){
         for(int i = 0; i < M; i++){
              edges[i].u = ++U[i]; edges[i].v = ++V[i];
              edges[i].w = W[i]; 
         }
         sort(edges,edges + M,cmp);
         E = N;
         for(int i = 1; i <= N; i++) fa[i] = i; 
         for(int i = 0; i < M; i++){
              int x = find(edges[i].u); int y = find(edges[i].v);
              E++; 
              if(x == y){
                   fa[x] = fa[E] = E;
                   adj[E].push_back(x); 
                   val[E] = edges[i].w;
                   cyc[E] = 1; 
              }
              else{
                   if(x < y) swap(x,y); 
                   fa[x] = fa[y] = fa[E] = E; 
                   adj[E].push_back(x);
                   adj[E].push_back(y); 
                   val[E] = edges[i].w;
              }
         }
         dfs_calc(E);
         stack<pair<int,int>>stk; 
         stk.push({2,0});
         for(int i = 1; i <= E; i++){
              int u = to[i]; 
              while(stk.size() and stk.top().first <= cyc[u]) stk.pop(); 
              lf[u] = stk.top().second; 
              stk.push({cyc[u],u});             
         }
         while(stk.size()) stk.pop();
         stk.push({2,0});
         for(int i = E; i > 0; i--){
              int u = to[i];
              while(stk.size() and stk.top().first <= cyc[u]) stk.pop();
              ri[u] = stk.top().second;   
              stk.push({cyc[u],u}); 
         }
}
int getMinimumFuelCapacity(int X, int Y){
      int anc = lca(++X,++Y);
      //cout<<anc<<endl;
      if(cyc[anc] or ri[anc]) return val[anc];
      if(lf[anc]) return val[lf[anc]];
      return -1;
      
}

Compilation message (stderr)

swap.cpp: In function 'void dfs_calc(int)':
swap.cpp:27:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |     for(int i = 0; i < adj[u].size(); i++){
      |                    ~~^~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 0 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27