Submission #828293

#	Time	Username	Problem	Language	Result	Execution time	Memory
828293		tolbi	Ancient Books (IOI17_books)	C++17	0 / 100	1 ms	256 KiB

books

#include <bits/stdc++.h>
using namespace std;
#include "books.h"
struct SegTree{
	vector<long long> segtree;
	SegTree(int n){
		segtree.resize((1LL<<((long long)(ceil(log2(n)+1))))-1,0ll);
	}
	void update(int node){
		node+=segtree.size()/2;
		segtree[node]++;
		while (node){
			node=(node-1)/2;
			segtree[node]++;
		}
	}
	long long query(int tarl, int tarr, int l = 0, int r = -1, int node = 0){
		if (r==-1) r = segtree.size()/2;
		if (l>=tarl && r<=tarr) return segtree[node];
		if (l>tarr || r<tarl) return 0ll;
		int mid = l+(r-l)/2;
		long long lnode = query(tarl, tarr, l, mid, node*2+1);
		long long rnode = query(tarl, tarr, mid+1, r, node*2+2);
		return lnode+rnode;
	}
};
long long minimum_walk(std::vector<int> p, int s) {
	//number of inversions*2+max pos such that p_i!=i-last non inversion
	//a*2+b-c
	long long a=0, b=-1, c=0;
	int n = p.size();
	SegTree segtree(n);
	for (int i = n-1; i >= 0; i--){
		if (p[i]!=i){
			b=i;
			break;
		}
	}
	if (b==-1) return 0;
	for (int i = 0; i < b; i++){
		if (p[i]<p[b]) c++;
	}
	for (int i = 0; i < n; i++){
		a+=segtree.query(p[i],n-1);
		segtree.update(p[i]);
	}
	return a*2+b-c;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 10
• Subtask 3: 0 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30