Submission #1063567

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063567		aaaaaarroz	Arranging Shoes (IOI19_shoes)	C++17	0 / 100	0 ms	348 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
template<class T, T m_(T, T)> struct IterativeSegmentTree{
  int n; vector<T> ST;
  IterativeSegmentTree(){}
  IterativeSegmentTree(vector<T> &a){
    n = a.size(); ST.resize(n << 1);
    for (int i=n;i<(n<<1);i++)ST[i]=a[i-n];
    for (int i=n-1;i>0;i--)ST[i]=m_(ST[i<<1],ST[i<<1|1]);
  }
  void update(int pos, T val){ // replace with val
    ST[pos += n] = val;
    for (pos >>= 1; pos > 0; pos >>= 1)
      ST[pos] = m_(ST[pos<<1], ST[pos<<1|1]);
  }
  T query(int l, int r){ // [l, r]
    T ansL, ansR; bool hasL = 0, hasR = 0;
    for (l += n, r += n + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1) 
        ansL=(hasL?m_(ansL,ST[l++]):ST[l++]),hasL=1;
      if (r & 1) 
        ansR=(hasR?m_(ST[--r],ansR):ST[--r]),hasR=1;
    }
    if (!hasL) return ansR; if (!hasR) return ansL;
    return m_(ansL, ansR);
  }
};
int merge(int a, int b){
	return a+b;
}
long long count_swaps(vector<int> s)
{
   vector< pair<int,int> > parejas;
   map<int,queue<int> > last;
   for (int i = int(s.size())-1; i >= 0; --i)
   {
      int x = s[i];
      if (!last[-x].empty())
      {
         parejas.emplace_back(i, last[-x].front());
         last[-x].pop();
      }
      else
         last[x].push(i);
   }
   reverse(parejas.begin(), parejas.end());
   long long ret = 0;
   vector<int>mudo(s.size(),0);
   IterativeSegmentTree<int,merge>st(mudo);
   for (auto p : parejas)
   {
      int l, r;
      tie(l, r) = p;
      int steps = r - l - 1 - st.query(l+1, r-1);
      if (s[l] > 0) {
         ++steps;
      }
      ret += steps;
      st.update(r, 1);
   }
    return ret;
}

Compilation message (stderr)

shoes.cpp: In member function 'T IterativeSegmentTree<T, m_>::query(int, int)':
shoes.cpp:24:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   24 |     if (!hasL) return ansR; if (!hasR) return ansL;
      |     ^~
shoes.cpp:24:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   24 |     if (!hasL) return ansR; if (!hasR) return ansL;
      |                             ^~
shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:54:48: warning: 'ansR' may be used uninitialized in this function [-Wmaybe-uninitialized]
   54 |       int steps = r - l - 1 - st.query(l+1, r-1);
      |                                                ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15