| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 701165 | Quan2003 | Swapping Cities (APIO20_swap) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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];
int deg[N + 1],deg1[N + 1],deg3[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,int p){
to[timer] = u;
in[u] = timer++;
if(!val[u]) val[u] = val[p];
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,u);
}
}
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);
if(deg[edges[i].u] == 1) deg1[x]--;
if(deg[edges[i].v] == 1) deg1[y]--;
deg[edges[i].u]++; deg[edges[i].v]++;
if(deg[edges[i].u] == 1) deg1[x]++;
else if(deg[edges[i].u] == 3) deg3[x]++;
if(deg[edges[i].v] == 1) deg1[y]++;
else if(deg[edges[i].v] == 3) deg3[y]++;
E++;
if(x == y){
fa[x] = fa[E] = E;
deg3[E] += deg3[x];
deg1[E] += deg1[x];
adj[E].push_back(x);
}
else{
//if(x < y) swap(x,y);
fa[x] = fa[y] = fa[E] = E;
deg3[E] += deg3[x] + deg3[y];
deg1[E] += deg1[x] + deg1[y];
adj[E].push_back(x);
adj[E].push_back(y);
}
if(!deg1[E] or deg3[E]) val[E] = edges[i].w;
}
for(int i = 1; i <= N + M; i++) if(fa[i] == i) dfs_calc(i,i);
}
int getMinimumFuelCapacity(int X, int Y){
if(find(++X) != find(++Y)) return -1;
int anc = lca(X,Y);
return val[anc];
}
int main(){
init(5, 6, {0, 0, 1, 1, 1, 2}, {1, 2, 2, 3, 4, 3}, {4, 4, 1, 2, 10, 3});
int ans = getMinimumFuelCapacity(1,2);
printf("%d",ans);
}