Submission #80156

#	Time	Username	Problem	Language	Result	Execution time	Memory
80156		Sherazin	Teleporters (IOI08_teleporters)	C++14	95 / 100	611 ms	66560 KiB

teleporters

#include <bits/stdc++.h>

#define pii pair<int, int>
#define x first
#define y second

using namespace std;

const int N = 2e6+2;

int n, m;
bitset<N> chk;
int sz[N], mp[N], pos[N], comp;
vector<int> dp(N);

int main() {
      scanf("%d %d", &n, &m);
      for(int i = 1, a, b; i <= n; i++) {
            scanf("%d %d", &a, &b);
            mp[a] = b, mp[b] = a;
            ++dp[a], ++dp[b];
      }
      int ptr = 0;
      for(int i = 1; i < N; i++) {
            dp[i] += dp[i-1];
            if(dp[i] != dp[i-1]) pos[ptr++] = i;
      }
      for(int i = 0; i < 2*n; i++) if(!chk[i]) {
            ++comp;
            chk[i] = true;
            int u = i;
            while(1) {
                  ++sz[comp];
                  int v = dp[mp[pos[u]]];
                  if(chk[v] || v == 2*n) break;
                  chk[v] = true;
                  u = v;
            }
      }
      int ans = sz[1];
      for(int i = 2; i <= comp; i++) dp[i-2] = sz[i];
      sort(dp.begin(), dp.begin()+comp-1, greater<int>());
      for(int i = 0; i < comp-1 && m; i++, m--) ans += dp[i] + 2;
      if(m) ans += 2*(m - (m & 1)) + (m & 1);
      printf("%d\n", ans);

      return 0;
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:17:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d %d", &n, &m);
       ~~~~~^~~~~~~~~~~~~~~~~
teleporters.cpp:19:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d", &a, &b);
             ~~~~~^~~~~~~~~~~~~~~~~

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