Submission #121773

#	Time	Username	Problem	Language	Result	Execution time	Memory
121773		LittleFlowers__	Bridges (APIO19_bridges)	C++14	100 / 100	2371 ms	17128 KiB

bridges

#include <bits/stdc++.h>
using namespace std;
const int sz=1<<10;
int pt=sz;
char buff[sz];
inline char readchar(){
    if(pt==sz){
        fread(buff,1,sz,stdin);
        pt=0;
    }
    return buff[pt++];
}
#define getchar readchar
#define in ({int x=0;int c=getchar(),n=0;for(;!isdigit(c);c=getchar()) n=(c=='-');for(;isdigit(c);c=getchar()) x=x*10+c-'0';n?-x:x;})
inline void out(int x){
    if(x>9) out(x/10);
    putchar(x%10+'0');
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r){return l+rng()%(r-l+1);}
#define fasty ios_base::sync_with_stdio(false),cin.tie(nullptr);
#define task "B"
#define forinc(a,b,c) for(int a=b,_c=c;a<=_c;++a)
#define fordec(a,b,c) for(int a=b,_c=c;a>=_c;--a)
#define forv(a,b) for(auto&a:b)
#define fi first
#define se second
#define pb push_back
#define ii pair<int,int>
#define mt make_tuple
#define all(a) a.begin(),a.end()
#define reset(f, x) memset(f, x, sizeof(f))
#define bit(x,i) ((x>>(i-1))&1)
#define on(x,i) (x|(1ll<<(i-1)))
#define off(x,i) (x&~(1<<(i-1)))

const int N=100010;

struct ed{
    int u,v,c,i;
}e[N];
struct qr{
    int o,u,x,i;
}q[N];
struct dt{
    int x,y,X,Y;
};
stack<dt> st;

int n,m,t;


int T=1000,mode;
int id[N],b[N],ans[N];
vector<int> mm[N];

inline int root(int x){
    return id[x]<0?x:root(id[x]);
}
inline void join(int x,int y){
    if((x=root(x))==(y=root(y))) return;
    if(mode){
        st.push({x,y,id[x],id[y]});
    }
    if(id[x]>id[y]) swap(x,y);
    id[x]+=id[y];
    id[y]=x;
}

int nxt[N*2],cur[N];

main(){
    //freopen(task".inp","r",stdin);
    //freopen(task".out","w",stdout);
    n=in;
    forinc(i,1,m=in) e[i]={in,in,in,i};
    forinc(i,1,t=in) q[i]={in,in,in,i};
    forinc(i,1,t){
        if(q[i].o==1) mm[q[i].u].pb(i);
        b[i]=(i-1)/T+1;
    }

    forinc(i,1,m) cur[i]=t+1;
    fordec(i,t,1) if(q[i].o==1){
        nxt[i]=cur[q[i].u];
        cur[q[i].u]=i;
    }
    forinc(i,1,m){
        nxt[i+t+1]=cur[i];
        cur[i]=i+t+1;
    }

    forinc(i,1,t){
        if(b[i]==b[i-1]) continue;
        vector<ed> E;
        vector<qr> Q;
        reset(id,-1);
        int j=i,l=i,r=b[i]*T > t ? t : b[i]*T;
        while(j<=t && b[j]==b[i]){
            if(q[j].o==2) Q.pb(q[j]);
            j++;
        }
        sort(all(Q),[](qr i,qr j){
            return i.x>j.x;
        });
        forinc(j,1,m){
            if(nxt[cur[j]]>r) E.pb(e[j]);
        }
        sort(all(E),[](ed i,ed j){
            return i.c>j.c;
        });
        int k=0;
        forinc(j,0,Q.size()-1){
            while(k<E.size() && E[k].c>=Q[j].x){
                join(E[k].u,E[k].v);
                k++;
            }
            mode=1;
            forinc(k,l,r) if(q[k].o==1){
                if(nxt[cur[q[k].u]]>r) continue;
                if(k<Q[j].i && nxt[k]>Q[j].i && q[k].x>=Q[j].x){
                    join(e[q[k].u].u,e[q[k].u].v);
                    continue;
                }
                if(nxt[cur[q[k].u]]>Q[j].i && e[q[k].u].c>=Q[j].x){
                    join(e[q[k].u].u,e[q[k].u].v);
                }
            }
            mode=0;
            ans[Q[j].i]=-id[root(Q[j].u)];
            while(st.size()){
                auto x=st.top(); st.pop();
                id[x.x]=x.X;
                id[x.y]=x.Y;
            }
        }
        forinc(j,l,r) if(q[j].o==1){
            e[q[j].u].c=q[j].x;
            cur[q[j].u]=j;
        }
    }
    forinc(i,1,t) if(q[i].o==2) out(ans[i]),putchar('\n');
}

Compilation message (stderr)

bridges.cpp:72:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^
bridges.cpp: In function 'int main()':
bridges.cpp:114:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             while(k<E.size() && E[k].c>=Q[j].x){
                   ~^~~~~~~~~
bridges.cpp: In function 'char readchar()':
bridges.cpp:8:14: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         fread(buff,1,sz,stdin);
         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 27 / 27