Submission #69359

#	Time	Username	Problem	Language	Result	Execution time	Memory
69359		Bruteforceman	Ancient Books (IOI17_books)	C++11	12 / 100	13 ms	9456 KiB

books

#include "books.h"
#include "bits/stdc++.h"
using namespace std;
int col[1000010];
bool vis[1000010];

bool v[1000010];
int l[1000010], r[1000010];
int cmp[1000010];

void dfs(int x, int c) {
	v[x] = true;
	for(int i = l[x]; i <= r[x]; i++) {
		cmp[i] = c;
		if(col[i] != -1 && v[col[i]] == false) {
			dfs(col[i], c);
		}
	}
}


long long minimum_walk(std::vector<int> p, int s) {
	long long ans = 0;
	int n = p.size();
	for(int i = 0; i < n-1; i++) {
		int go_left = 0;
		int go_right = 0;
		for(int j = 0; j <= i; j++) {
			if(p[j] > i) {
				++go_left;
			}
		}
		for(int j = i + 1; j < n; j++) {
			if(p[j] < i+1) {
				++go_right;
			}
		}
		assert(go_left == go_right);
		ans += go_left + go_right;
	}
	memset(col, -1, sizeof col);
	memset(v, false, sizeof v);

	int id = 0;
	for(int i = 0; i < n; i++) {
		if(col[i] != -1 || p[i] == i) continue;
		int cur = i;
		++id;
		l[id] = n;
		r[id] = 0; 
		while(col[cur] == -1) {
			l[id] = min(l[id], cur);
			r[id] = max(r[id], cur);
			col[cur] = id;
			cur = p[cur];
		}
	}
	memset(cmp, -1, sizeof cmp);
	int c = 0;
	for(int i = 1; i <= id; i++) {
		if(v[i] == false) {
			dfs(i, ++c);
		}	
	}
	for(int i = 0; i < n; i++) {
		col[i] = cmp[i];
	}
	int p1 = 0;
	int p2 = n-1;
	while(col[p1] == -1 && p1 < s) {
		++p1;
	}
	while(col[p2] == -1 && p2 > s) {
		--p2;
	}
	for(int i = p1; i < p2; i++) {
		if(col[i] == -1 || col[i + 1] == -1) {
			ans += 2;
		}
	}
	return ans;
}

// 30 0
// 17 28 26 18 29 8 23 9 22 20 16 3 7 24 5 19 4 2 11 25 0 14 6 13 1 12 21 27 15 10 

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