Submission #313900

#	Time	Username	Problem	Language	Result	Execution time	Memory
313900		nikatamliani	Split the Attractions (IOI19_split)	C++14	18 / 100	183 ms	26360 KiB

split

#include <bits/stdc++.h>
#define vi vector < int >
#include "split.h"
using namespace std;
const int N = 2e5 + 10;
int in[N], out[N], sub[N], P[N];
int countA, countB, countC, aa = 1, bb = 2, cc = 3;
bool vis[N];
int timer = 0;
vi edges[N], redges[N], ans;
void dfs(int x, int p) {
    if(vis[x]) return;
    vis[x] = sub[x] = 1; 
    for(int to : edges[x]) {
        if(to != p) {
            if(!vis[to]) {
                P[to] = x;
                dfs(to, x);
                sub[x] += sub[to];
                redges[to].push_back(x);
                redges[x].push_back(to);
            }
        }
    }
}
void reroot(int x, int p) {
    in[x] = ++timer;
    sub[x] = 1;
    for(int to : redges[x]) {
        if(to != p) {
            reroot(to, x);
            sub[x] += sub[to];
        }
    }
    out[x] = ++timer;
}
void find_answer(int x, int p, int v) {
    if(in[v] <= in[x] && out[v] >= out[x]) {
        if(countA > 0) {
            ans[x] = aa;
            --countA;
        } 
    } else {
        if(countB > 0) {
            ans[x] = bb;
            --countB;
        }
    }
    for(int to : redges[x]) {
        if(to != p) {
            find_answer(to, x, v);
        }
    }
}
int find_best(int x, int p) {
    int a = countA, c = countC;
    for(int to : redges[x]) {
        if(to != p) {
            if(sub[to] >= a && sub[to] <= c + a) {
                return x;
            } 
        } else {
            if(sub[0] - sub[to] >= a && sub[0] - sub[to] <= c + a) {
                return x;
            }
        }
    }
    for(int to : redges[x]) {
        if(to != p && sub[to] > c + a) {
            return find_best(to, x);
        }
    }
    return -1;
}
vi find_split(int n, int a, int b, int c, vi p, vi q) {
    ans.resize(n);
    if(a > b) swap(a, b), swap(aa, bb);
    if(b > c) swap(b, c), swap(bb, cc);
    if(a > b) swap(a, b), swap(aa, bb);
    countA = a, countB = b, countC = c;
    for(int i = 0; i < q.size(); ++i) {
        edges[q[i]].push_back(p[i]);
        edges[p[i]].push_back(q[i]);
    }
    dfs(0, -1);
    int root = find_best(0, -1), from = -1;
    if(root == -1) return ans;
    reroot(root, -1);
    for(int x : redges[root]) {
        if(sub[x] >= a && sub[x] <= c + a) {
            from = x;
        }
    }
    find_answer(root, -1, from);
    for(int i = 0; i < n; ++i) if(ans[i] == 0) ans[i] = cc;
    return ans;
}

Compilation message (stderr)

split.cpp: In function 'void dfs(int, int)':
split.cpp:13:21: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   13 |     vis[x] = sub[x] = 1;
      |              ~~~~~~~^~~
split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:81:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |     for(int i = 0; i < q.size(); ++i) {
      |                    ~~^~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 0 / 22
• Subtask 4: 0 / 24
• Subtask 5: 0 / 36