Submission #140742

#	Time	Username	Problem	Language	Result	Execution time	Memory
140742		rzbt	Evacuation plan (IZhO18_plan)	C++14	0 / 100	588 ms	524292 KiB

plan

#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define MAXN 200005

using namespace std;

int n,m,q;
vector<int> niz[MAXN];
int predak[MAXN][21];
int dubina[MAXN];
int a[MAXN];

set<int> s[MAXN],sp[MAXN];

void dfs(int t,int o,int h){
    predak[t][0]=o;
    dubina[t]=h;
    for(auto x:niz[t])
        if(x!=o)
            dfs(x,t,h+1);

}

int lca(int a, int b){
    if(dubina[b]>dubina[a])swap(a,b);
    for(int j=20;j>=0;j--){
        if(dubina[predak[a][j]]>=dubina[b])a=predak[a][j];
    }
    if(a==b)return a;
    for(int j=20;j>=0;j--){
        if(predak[a][j]!=predak[b][j]){
            a=predak[a][j];
            b=predak[b][j];
        }
    }
    return predak[a][0];

}

int main()
{
    scanf("%d %d %d", &n, &m, &q);
    for(int i=1;i<n;i++){
        int t1,t2;
        scanf("%d %d", &t1, &t2);
        niz[t1].pb(t2);
        niz[t2].pb(t1);
    }
    dfs(1,0,1);
    for(int j=1;j<21;j++)
        for(int i=1;i<=n;i++)
            predak[i][j]=predak[i][predak[i][j-1]];
    for(int i=1;i<=m;i++)
        scanf("%d",a+i);
    for(int i=1;i<m;i++)
        s[lca(a[i],a[i+1])].insert(i);
    for(int i=1;i<=m;i++)
        sp[a[i]].insert(i);
    while(q--){
        int qt; //FITTER HAPPIER MORE PRODUCTIVE
        scanf("%d", &qt);
        if(qt==1){
            int pos,x;
            scanf("%d %d", &pos,&x);
            if(pos!=1)s[lca(a[pos],a[pos-1])].erase(pos-1);
            if(pos!=m)s[lca(a[pos],a[pos+1])].erase(pos);
            sp[a[pos]].erase(pos);
            a[pos]=x;
            if(pos!=1)s[lca(a[pos],a[pos-1])].insert(pos-1);
            if(pos!=m)s[lca(a[pos],a[pos+1])].insert(pos);
            sp[a[pos]].insert(pos);


        }else if(qt==2){

            int l,r,x;
            scanf("%d %d %d", &l, &r, &x);
            //printf("    %d %d\n",sp[x].size(),s[x].size());
            int t1=0,t2=0;
            if(!sp[x].empty() && sp[x].lower_bound(l)!=sp[x].end())t1=*(sp[x].lower_bound(l));
            if(!s[x].empty() && s[x].lower_bound(l)!=s[x].end())t2=*(s[x].lower_bound(l));
            //printf("    %d %d    %d %d\n",sp[x].size(),s[x].size(),t1,t2);
            if(t1<=r && t1)printf("%d %d\n",t1,t1);
            else if(t2<r && t2)printf("%d %d\n",t2,t2+1);
            else printf("-1 -1\n");
        }
        else{
            int x,y;
            scanf("%d %d", &x, &y);
            printf("    %d\n",lca(a[x],a[y]));
        }
    }





    return 0;
}

Compilation message (stderr)

plan.cpp: In function 'int main()':
plan.cpp:46:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &n, &m, &q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:49:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &t1, &t2);
         ~~~~~^~~~~~~~~~~~~~~~~~~
plan.cpp:58:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",a+i);
         ~~~~~^~~~~~~~~~
plan.cpp:65:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &qt);
         ~~~~~^~~~~~~~~~~
plan.cpp:68:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d", &pos,&x);
             ~~~~~^~~~~~~~~~~~~~~~~~
plan.cpp:81:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d %d", &l, &r, &x);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:93:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d", &x, &y);
             ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46