Submission #313857

#	Time	Username	Problem	Language	Result	Execution time	Memory
313857		nikatamliani	Split the Attractions (IOI19_split)	C++14	11 / 100	144 ms	13948 KiB

split

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

Compilation message (stderr)

split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:67:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |     for(int i = 0; i < q.size(); ++i) {
      |                    ~~^~~~~~~~~~
split.cpp:84:17: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   84 |     if(p.size() != n - 1) return ans;
      |        ~~~~~~~~~^~~~~~~~
split.cpp:97:18: warning: 'subTree' may be used uninitialized in this function [-Wmaybe-uninitialized]
   97 |     find_children(good, -1, subTree, ans, edges);
      |     ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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