Submission #137285

#	Time	Username	Problem	Language	Result	Execution time	Memory
137285		choikiwon	Ancient Books (IOI17_books)	C++17	0 / 100	42 ms	31736 KiB

books

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

typedef long long ll;
typedef pair<int, int> pii;

const int maxn = 1000010;

int fa[maxn], sz[maxn];
void init() {
    for(int i = 0; i < maxn; i++) {
        fa[i] = i;
        sz[i] = 1;
    }
}
int find(int u) {
    if(fa[u] == u) return u;
    else return fa[u] = find(fa[u]);
}
void mrg(int u, int v) {
    u = find(u);
    v = find(v);
    if(u == v) return;
    fa[v] = u;
    sz[u] += sz[v];
}

int N, S;
int A[maxn], vis[maxn];
vector<pii> E[maxn];

ll minimum_walk(std::vector<int> p, int s) {
	N = p.size();
	S = s;
	for(int i = 0; i < N; i++) {
        A[i] = p[i];
	}

	init();

	ll ret = 0;
	for(int i = 0; i < N; i++) {
        if(vis[i]) continue;

        int mx = i;

        int u = i;
        while(!vis[u]) {
            vis[u] = 1;
            mx = max(mx, u);

            ret += abs(u - A[u]);
            mrg(u, A[u]);
            u = A[u];
        }
	}

	int st = -1;
	for(int i = 0; i < N; i++) {
        if(i == S || sz[ find(i) ] > 1) {
            if(st != -1) {
                E[i - st].push_back(pii(st, i));
            }
            st = i;
        }
	}

	for(int i = 1; i <= N; i++) {
        for(int j = 0; j < E[i].size(); j++) {
            int u = E[i][j].first;
            int v = E[i][j].second;

            if(find(u) != find(v)) {
                ret += 2 * i;
                mrg(u, v);
            }
        }
	}

	return ret;
}

Compilation message (stderr)

books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:70:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0; j < E[i].size(); j++) {
                        ~~^~~~~~~~~~~~~

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