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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#524897#7937. Fast XORtingnathan4690TL 2ms11148kbC++172.1kb2024-08-20 10:10:262024-08-20 10:10:26

Judging History

你现在查看的是最新测评结果

  • [2024-08-20 10:10:26]
  • 评测
  • 测评结果:TL
  • 用时:2ms
  • 内存:11148kb
  • [2024-08-20 10:10:26]
  • 提交

answer

// Fast XORting
#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define el cout << '\n'
#define f1(i,n) for(ll i=1;i<=n;i++)
#define __file_name ""
using namespace std;
const ll maxn = 1e6+5, inf=1e18;

struct FenwickTree{
    ll n;
    vector<ll> bit;
    FenwickTree(ll n): n(n), bit(n+1, 0ll){};
    void update(ll idx, ll v){for(;idx<=n;idx+=idx&-idx) bit[idx] += v;}
    ll getSum(ll idx){
        ll res = 0;
        for(;idx>0;idx-=(idx&-idx)) res += bit[idx];
        return res;
    }
};

ll n,a[maxn],ans;
vector<ll> all;
bool flag;

ll solve(const vector<ll> &v, ll bit, ll val){
    ll ans = 0;
    ll c0 = 0, a0 = 0, c1 = 0, a1 = 0;
    vector<ll> v0, v1;
    for(ll i=v.size()-1;i>=0;i--){
        ll item = v[i];
        if(((item & (1 << bit)) != val)) {
            v1.push_back(item);
            c1++;
            a1 += c0;
        }else {
            v0.push_back(item);
            c0++;
        }
    }
    reverse(v0.begin(), v0.end());
    reverse(v1.begin(), v1.end());
    // cout << bit << ' ' << a0 << ' ' << a1;el;
    ans += a1;
    if(bit){
        ll vv0 = solve(v0, bit-1, 0) + solve(v1, bit-1, 0);
        ll vv1 = solve(v0, bit-1, 1) + solve(v1, bit-1, 1);
        // if(vv1 > vv0) flag = false;
        ans += min(vv0, vv1);
    }
    return ans;
}

FenwickTree fen(maxn);

int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    if(fopen(__file_name ".inp", "r")){
        freopen(__file_name ".inp","r",stdin);
        freopen(__file_name ".out","w",stdout);
    }
    // code here
    cin >> n;
    f1(i,n) {
        cin >> a[i];
        // cout << bitset<3>(a[i]).to_string();el;
    }
    ll preans = 0;
    for(ll i=n;i>=1;i--){
        preans +=fen.getSum(a[i]);
        fen.update(a[i] + 1, 1);
    }
    f1(i,n) all.push_back(a[i]);
    flag = true;
    ll vv0 = solve(all, __lg(n) - 1, 0);
    ll vv1 = solve(all, __lg(n) - 1, 1);
    // if(vv1 > vv0) flag = false;
    cout << min(min(vv0, vv1) + 1, preans);
    return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 2ms
memory: 11148kb

input:

8
0 1 3 2 5 4 7 6

output:

2

result:

ok 1 number(s): "2"

Test #2:

score: 0
Accepted
time: 2ms
memory: 10956kb

input:

8
2 0 1 3 4 5 6 7

output:

2

result:

ok 1 number(s): "2"

Test #3:

score: -100
Time Limit Exceeded

input:

262144
47482 131703 90418 122675 166494 247529 196154 16950 66501 50357 246808 25929 10418 50538 26955 151884 63776 58023 20073 26544 74785 44064 41836 148543 87920 54172 3270 131495 130960 112122 167229 215767 77499 195004 21391 11039 168999 256346 109690 180904 172679 157200 78594 201857 52784 147...

output:


result: