Submission #1063546

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063546		aaaaaarroz	Arranging Shoes (IOI19_shoes)	C++17	0 / 100	1 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> v) {
	int n=v.size();
	vector<int>vacio(n,0);
	IterativeSegmentTree<int,merge>st(vacio);
	long long cnt=0;
	map<int, pair<int,int>>pos;
	int position=0;
	for(int zapato:v){
		if(zapato<0){
			pos[zapato].first=position;
		}
		else{
			pos[zapato].second=position;
		}
		position++;
	}
	for(auto &nose:pos){
		int der=st.query(nose.second.second,n-1);
		int izq=st.query(0,nose.second.first);
		bool menor=(nose.second.first<nose.second.second);
		cnt+=(der-izq-menor);
		st.update(der,1);
		st.update(izq,1);
	}
	return cnt;
}

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:12:12: warning: 'ansR' may be used uninitialized in this function [-Wmaybe-uninitialized]
   12 |     ST[pos += n] = val;
      |        ~~~~^~~~
shoes.cpp:17:13: note: 'ansR' was declared here
   17 |     T ansL, ansR; bool hasL = 0, hasR = 0;
      |             ^~~~
shoes.cpp:12:12: warning: 'ansR' may be used uninitialized in this function [-Wmaybe-uninitialized]
   12 |     ST[pos += n] = val;
      |        ~~~~^~~~
shoes.cpp:17:13: note: 'ansR' was declared here
   17 |     T ansL, ansR; bool hasL = 0, hasR = 0;
      |             ^~~~

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