Submission #877074

#	Time	Username	Problem	Language	Result	Execution time	Memory
877074		raul2008487	Arranging Shoes (IOI19_shoes)	C++17	0 / 100	0 ms	348 KiB

shoes

#include "shoes.h"
#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define all(v) v.begin(), v.end()
#define fi first
#define se second
#define in insert
using namespace std;
const int sz = 2e5+5;
ll Tree[sz];
void add(ll pos, ll val){
    for(ll i = pos; i<sz ; i += (i & (-i))){
        Tree[i] += val;
    }
}
ll get(ll pos){
    ll rx = 0;
    for(ll i = pos; i>0; i -= (i & (-i))){
        rx += Tree[i];
    }
    return rx;
}
ll ask(ll l, ll r){
    return get(r) - get(l-1);
}
long long count_swaps(vector<int> s) {
	ll n = s.size(), i, j, ans = 0;
	set<pair<int,int>> c;
	for(i=0;i<n;i++){
        c.in({s[i], i});
        add(i+1, 1);
	}
	for(i=0;i<n;i++){
        if(c.find({s[i], i}) == c.end()){continue;}
        ll ix = (*c.lower_bound({-s[i], i})).se;
        if(ix >= (i+2)){
            ans += ask(i+2, ix);
        }
        if(s[i] > 0){
            ans++;
        }
        add(i+1, -1);
        add(ix+1, -1);
        c.erase({s[i], i});
        c.erase({-s[i], i});
	}
    return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:28:22: warning: unused variable 'j' [-Wunused-variable]
   28 |  ll n = s.size(), i, j, ans = 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