Submission #1066998

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066998		vjudge1	Untitled (POI11_rot)	C++14	100 / 100	164 ms	23888 KiB

Main

#include <bits/stdc++.h>
#define file(name)  if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define REV(i, b, a) for(int i = (b); i >= (a); --i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define ll long long
#define fi first
#define se second
#define int long long
using namespace std;
const int N = 2e5 + 5;


int cnt, node;
int n;
int l[2 * N], r[2 * N];
int st[2 * N], ed[2 * N];
int a[N];
struct BIT {
	int tree[N];
	void add(int x, int v){
		while(x <= n){
			tree[x] += v;
			x += x & -x;
		}
	}
	int query(int x){
		int ret = 0;
		while(x) ret += tree[x], x -= x & -x;
		return ret;
	}
} bit;

void read_tree(int v){
	int x; cin >> x;
	st[v] = cnt;
	if(x == 0){
		l[v] = ++node;
		read_tree(node);
		r[v] = ++node;
		read_tree(node);
	}
	else a[cnt++] = x;
	ed[v] = cnt;
}

int dfs(int v){
	if(ed[v] - st[v] == 1){
		bit.add(a[st[v]], 1);
		return 0;
	}
	int ls = ed[l[v]] - st[l[v]];
	int rs = ed[r[v]] - st[r[v]];
	int ans1 = 0, ans2 = 0;
	if(ls < rs){
		ans1 += dfs(l[v]);

		FOR(i, st[l[v]], ed[l[v]] - 1) {
			bit.add(a[i], -1);
		}
		ans1 += dfs(r[v]);
		FOR(i, st[l[v]], ed[l[v]] - 1) {
			ans2 += bit.query(a[i]);
		}
		FOR(i, st[l[v]], ed[l[v]] - 1) {
			bit.add(a[i], 1);
		}
	}
	else {
		ans1 += dfs(r[v]);
		FOR(i, st[r[v]], ed[r[v]] - 1) {
			bit.add(a[i], -1);
		}
		ans1 += dfs(l[v]);
		FOR(i, st[r[v]], ed[r[v]] - 1) {
			ans2 += ls - bit.query(a[i]);
		}
		FOR(i, st[r[v]], ed[r[v]] - 1) {
			bit.add(a[i], 1);
		}
	}
	return ans1 + min(ls * rs - ans2, ans2);
}

void solve(int tc) {
    cin >> n;
    read_tree(0);
    cout << dfs(0) << '\n';
    return;
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    int tc = 1;
    // cin >> tc;
    for(int i = 1; i <= tc; ++i) solve(tc);
    return (0);
}

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 9 / 9
• Subtask 7: 9 / 9
• Subtask 8: 9 / 9
• Subtask 9: 9 / 9
• Subtask 10: 9 / 9
• Subtask 11: 10 / 10