Submission #1064235

#	Time	Username	Problem	Language	Result	Execution time	Memory
1064235		TsotneSV	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	210 ms	274340 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
/* /\_/\
  (= ._.)
  / >  \>
*/
//#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") // codeforces

// #define int long long
#define fi first
#define se second
#define pb push_back
#define ins insert
#define mp make_pair
#define send {ios_base::sync_with_stdio(false);}
#define help {cin.tie(0);}
#define endl '\n'
#define sz(x) ((long long) (x).size())
#define all(x) (x).begin(),(x).end()
#define print(x) cout<<(x)<<" ";
#define printl(x) cout<<(x)<<endl
#define dbg(x) cerr<<#x<<" "<<x<<endl

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

void fileIO(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

// const ll mod = 1000000007;
// const ll mod = 998244353;
// ll mod;

const int inf=1e9,MAXN=2e5+5; 
const ll INF=1e18; 
const ld pi = 3.14159265358979323846;

struct BIT {
    int n; vi S;

    void update(int pos,int add) {
        for(pos;pos<=n;pos+=pos&-pos) S[pos]+=add;
    }

    int sum(int pos) {
        int ret=0;
        for(pos;pos>0;pos-=pos&-pos) ret += S[pos];
        return ret;
    }

    int query(int l,int r) {
        if(r < l) return 0;
        return sum(r) - sum(l-1);
    }

    BIT(vi v) {
        n = v.size();
        S = vi(n+1,0);
        for(int i=0;i<n;i++) update(i+1,v[i]);
    }
};

long long count_swaps(std::vector<int> S) {

    int n = S.size();

    BIT bit(vi(n+1,0));

    queue<int> pos[2][n+1];
    bool marked[n+1] = {0};

    for(int i=0;i<n;i++) {
        if(S[i] < 0) pos[0][-S[i]].push(i+1);
        else pos[1][S[i]].push(i+1);
    }

    ll ans = 0;

    for(int i=0;i<n;i++) {
        if(marked[i+1]) continue;
        if(S[i] > 0) {
            int x = pos[0][S[i]].front();
            pos[0][S[i]].pop();
            ans += x - i - 1 - bit.query(i+1,x);
//dbg(ans);
            bit.update(x,1);
            marked[x] = 1;
            pos[1][S[i]].pop();
        }else {
            int x = pos[1][-S[i]].front(); pos[1][-S[i]].pop();
            ans += x - i - 2 - bit.query(i+1,x);
            bit.update(x,1);
            marked[x] = 1;
            pos[0][-S[i]].pop();
        }
    }

    return ans;

}

/*int main() {
    print(count_swaps({-1,2,1,-2,3,-3}));
}*/

Compilation message (stderr)

shoes.cpp: In member function 'void BIT::update(int, int)':
shoes.cpp:54:13: warning: statement has no effect [-Wunused-value]
   54 |         for(pos;pos<=n;pos+=pos&-pos) S[pos]+=add;
      |             ^~~
shoes.cpp: In member function 'int BIT::sum(int)':
shoes.cpp:59:13: warning: statement has no effect [-Wunused-value]
   59 |         for(pos;pos>0;pos-=pos&-pos) ret += S[pos];
      |             ^~~
shoes.cpp: In function 'void fileIO(std::string)':
shoes.cpp:38:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
shoes.cpp:39:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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