Submission #1607746

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;

map<pll, ll> mp;

int main(void) {
  int n;
  cin >> n;

  ll s, g;
  cin >> s >> g;

  vector<int> l(n + 1), r(n + 1);
  for (int i = 0; i <= n; i++) {
    cin >> l[i] >> r[i];
  }

  ll pos = s, cnt = 1;
  // double ans = 0.0;
  for (int i = 1; i < n; i++) {
    if (l[i] <= pos && pos <= r[i]) {
      cnt++;
    } else if (pos < l[i]) {
      mp[pll(l[i] - pos, cnt)]++;
      // v.push_back(pll(l[i] - pos, cnt));
      // ans += hypot(l[i] - pos, cnt);
      pos = l[i];
      cnt = 1;
    } else if (pos > r[i]) {   
      mp[pll(r[i] - pos, cnt)]++;
      // v.push_back(pll(pos - r[i], cnt));
      // ans += hypot(pos - r[i], cnt);
      pos = r[i];
      cnt = 1;
    }
  }
  // ans += hypot(g - pos, cnt);
  // v.push_back(pll(g - pos, cnt));
  mp[pll(g - pos, cnt)]++;

  double ans = 0.0;
  for (auto i : mp) {
    ll a = i.first.first * i.second, b = i.first.second * i.second;
    ans += sqrt(a * a + b * b);
  }

  printf("%.15f\n", ans);

  return 0;
}

Submission Info

Judge Result