Submission #884487

#	Time	Username	Problem	Language	Result	Execution time	Memory
884487		tsumondai	Money (IZhO17_money)	C++14	0 / 100	3 ms	8284 KiB

money

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define foru(i, l, r) for(int i = l; i <= r; i++)
#define ford(i, r, l) for(int i = r; i >= l; i--)
#define __TIME  (1.0 * clock() / CLOCKS_PER_SEC)

typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<ii, ii> iiii;
 
const int N = 1e6 + 5;
 
const int oo = 1e9, mod = 1e9 + 7;
 
int n, m, k, a[N];
vector<int> bit1(N), bit2(N);

void updatePoint(vector<int>& b, int u, int v) {
    int idx = u;
    while (idx <= n) {
        b[idx] += v;
        idx += (idx & (-idx));
    }
}

void updateRange(int l, int r, int v) {
    updatePoint(bit1, l, (n - l + 1) * v);
    updatePoint(bit1, r + 1, -(n - r) * v);
    updatePoint(bit2, l, v);
    updatePoint(bit2, r + 1, -v);
}

int getSumOnBIT(vector<int>& b, int u) {
    int idx = u, ans = 0;
    while (idx > 0) {
        ans += b[idx];
        idx -= (idx & (-idx));
    }
    return ans;
}

int prefixSum(int u) {
    return getSumOnBIT(bit1, u) - getSumOnBIT(bit2, u) * (n - u);
}

int rangeSum(int l, int r) {
    return prefixSum(r) - prefixSum(l - 1);
}

void process() {
	cin >> n;
	foru(i,1,n) cin >> a[i];
	int ans=0, pre=0;
	foru(i,1,n-1) {
		if (i<n && a[i] > a[i+1]) {
			ans++;
			updateRange(pre+1, i, 1);
			pre=i;
			continue;
		}
		if (a[i]==a[i+1]) continue;

		if (rangeSum(a[i+1]-1, a[i+1] - 1) -rangeSum(a[pre+1], a[pre+1])>0) {
			ans++;
			updateRange(pre+1, i, 1);
			pre=i;
		}
	}
	cout << ans+1;
    return;
}

signed main() {
    cin.tie(0)->sync_with_stdio(false);
    //freopen(".inp", "r", stdin);
    //freopen(".out", "w", stdout);
    process();
    cerr << "Time elapsed: " << __TIME << " s.\n";
    return 0;
}

// dont stop

• Subtask 1: 0 / 9
• Subtask 2: 0 / 16
• Subtask 3: 0 / 20
• Subtask 4: 0 / 55