Submission #257751

#	Time	Username	Problem	Language	Result	Execution time	Memory
257751		peti1234	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	76 ms	12536 KiB

shoes

#include <bits/stdc++.h>

using namespace std;
#define lsb(i) ((i) & -(i))
const int c=200002;
int n, t[c], p[c], k;
long long ans;
vector<int> sz[c];
vector<int> x;
int ask(int a) {
    int sum=0;
    while(a) sum+=t[a], a-=lsb(a);
    return sum;
}
int add(int a) {
    while(a<=n) t[a]++, a+=lsb(a);
}
long long count_swaps(vector<int> s) {
    n=s.size(), k=n/2;
    for (int i=0; i<n; i++) {
        int x=s[i], y=abs(x)+k, h=i+1;
        if (x<0) x*=-1, swap(x, y);
        if(sz[y].size()>p[y]) {
            int pos=sz[y][p[y]];
            p[y]++;
            if (x>k) ans++;
            ans+=ask(h)-ask(pos);
            add(pos);
        } else sz[x].push_back(h), add(h);
    }
    return ans;
}
/*
int main()
{
    cin >> n;
    for (int i=0; i<2*n; i++) {
        int a; cin >> a;
        x.push_back(a);
    }
    cout << count_swaps(x);
    return 0;
}
*/

Compilation message (stderr)

shoes.cpp: In function 'int add(int)':
shoes.cpp:17:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:23:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(sz[y].size()>p[y]) {
            ~~~~~~~~~~~~^~~~~

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