Submission #217546

#	Time	Username	Problem	Language	Result	Execution time	Memory
217546		mhy908	Teleporters (IOI08_teleporters)	C++14	100 / 100	493 ms	30356 KiB

teleporters

#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sortvec(x) sort(all(x))
#define compress(x) x.erase(unique(all(x)), x.end())
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
typedef pair<LL, LL> pll;
typedef pair<int, LL> pil;
typedef pair<LL, int> pli;
const int st=1, fin=4000002, MAXN=2000000;
int n;
LL k, ans;
bool ch[2000010], ch2[2000010];
int link[4000010];
LL dfs(int num, int finnum){
    //printf("! %d %d\n", num, finnum);
    if(num%2==0)ch2[num/2]=true;
    if(num==finnum)return 0;
    return 1+dfs(link[num], finnum);
}
vector<LL> vc;
int main(){
    scanf("%d %lld", &n, &k);
    for(int i=1; i<=n; i++){
        int a, b;
        scanf("%d %d", &a, &b);
        link[2*a]=2*b+1;
        link[2*b]=2*a+1;
        ch[a]=ch[b]=true;
    }
    ch[MAXN+1]=true;
    int pv=0;
    for(int i=1; i<=MAXN+1; i++){
        if(ch[i]){
            link[2*pv+1]=2*i;
            pv=i;
        }
    }
    ans=dfs(st, fin)/2;
    for(int i=1; i<=MAXN; i++){
        if(!ch[i]||ch2[i])continue;
        vc.pb((dfs(link[2*i], 2*i)+1)/2);
    }
    sort(all(vc), greater<LL>());
    for(auto i:vc){
        ans+=i+2;
        k--;
        if(!k)break;
    }
    ans+=(k+1)/2+k/2*3;
    printf("%lld", ans);
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %lld", &n, &k);
     ~~~~~^~~~~~~~~~~~~~~~~~~
teleporters.cpp:31:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
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• Subtask 20: 5 / 5