Submission #117064

#	Time	Username	Problem	Language	Result	Execution time	Memory
117064		JohnTitor	007 (CEOI14_007)	C++11	100 / 100	272 ms	17656 KiB

007

#include <bits/stdc++.h>
using namespace std;
#define FOR(i, j, k) for(int i=(j); i<=(k); i++)
#define FFOR(i, j, k) for(int i=(j); i<(k); i++)
#define DFOR(i, j, k) for(int i=(j); i>=(k); i--)
#define bug(x) cerr<<#x<<" = "<<(x)<<'\n'
#define pb push_back
#define mp make_pair
#define bit(s, i) (((s)>>(i))&1LL)
#define mask(i) ((1LL<<(i)))
#define builtin_popcount __builtin_popcountll
#define __builtin_popcount __builtin_popcountll
using ll=long long; using ld=long double;
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); const ld pi=acos(0)*2;
template <typename T> inline void read(T &x){char c; bool nega=0; while((!isdigit(c=getchar()))&&(c!='-')); if(c=='-'){nega=1; c=getchar();} x=c-48; while(isdigit(c=getchar())) x=x*10+c-48; if(nega) x=-x;}
template <typename T> inline void writep(T x){if(x>9) writep(x/10); putchar(x%10+48);}
template <typename T> inline void write(T x){if(x<0){ putchar('-'); x=-x;} writep(x);}
template <typename T> inline void writeln(T x){write(x); putchar('\n');}
#define taskname "007"
int n, m;
int s, d, a, b;
int a1, a2, b1, b2, w1, w2;
int fa[200001];
bool donea[200001];
int fb[200001];
bool doneb[200001];
vector <int> g[200001];
queue <int> q;
void bfs(int s, int *f, bool *done){
    FOR(i, 1, n) done[i]=0;
    f[s]=0;
    done[s]=1;
    q.push(s);
    while(!q.empty()){
        s=q.front();
        q.pop();
        for(int v: g[s]) if(!done[v]){
            done[v]=1;
            f[v]=f[s]+1;
            q.push(v);
        }
    }
}
int dp[200001];
bool done[200001];
int DP(int u){
    if(done[u]) return dp[u];
    done[u]=1;
    for(int v: g[u]) if(fa[v]<fa[u]&&fb[v]<fb[u]) dp[u]=max(dp[u], DP(v)+1);
    return dp[u];
}
int main(){
    #ifdef Aria
        if(fopen(taskname".in", "r"))
            freopen(taskname".in", "r", stdin);
    #endif // Aria
    read(n);
    read(m);
    read(s);
    read(d);
    read(a);
    read(b);
    {
        int u, v;
        FOR(i, 1, m){
            read(u);
            read(v);
            g[u].pb(v);
            g[v].pb(u);
        }
    }
    bfs(a, fa, donea);
    bfs(b, fb, doneb);
    a1=fa[s];
    a2=fa[d];
    b1=fb[s];
    b2=fb[d];
    w1=a2-a1;
    w2=b2-b1;
    if(w1<0||w2<0){
        puts("-1");
        return 0;
    }
    else if(w1!=w2){
        writeln(min(w1, w2));
    }
    else{
        int x=DP(s);
        int y=DP(d);
        if(x+w1>=y) writeln(w1);
        else writeln(w1-1);
    }
}

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70