Submission #140749

#	Time	Username	Problem	Language	Result	Execution time	Memory
140749		rzbt	Birthday gift (IZhO18_treearray)	C++14	100 / 100	1771 ms	77560 KiB

treearray

    #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[predak[i][j-1]][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)

treearray.cpp: In function 'int main()':
treearray.cpp:46:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &n, &m, &q);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
treearray.cpp:49:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d", &t1, &t2);
             ~~~~~^~~~~~~~~~~~~~~~~~~
treearray.cpp:58:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d",a+i);
             ~~~~~^~~~~~~~~~
treearray.cpp:65:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d", &qt);
             ~~~~~^~~~~~~~~~~
treearray.cpp:68:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
                 scanf("%d %d", &pos,&x);
                 ~~~~~^~~~~~~~~~~~~~~~~~
treearray.cpp:81:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
                 scanf("%d %d %d", &l, &r, &x);
                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
treearray.cpp:93:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
                 scanf("%d %d", &x, &y);
                 ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 26 / 26
• Subtask 4: 44 / 44