Submission #1602622

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Source Code Expand

#include <iostream>
#include <cmath>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
#include <cassert>

using namespace std;

vector < vector < int > > graph;
int n, A[100050], B[100050], d[100050];
///            round, depth, node
priority_queue < pair < int, pair < int, int > > > q;

void dfs(int node, int par, int dep)
{
    d[node] = dep;
    if(!graph[node].size())
    {
        B[node] = 1;
        q.push({0, {-d[node], node}});
    }
    for(int i = 0;i < graph[node].size();++i)
    {
        int to = graph[node][i];
        if(to != par)
            dfs(to, node, dep + 1);
    }
}

int main()
{
    scanf("%d", &n);
    graph.resize(n + 5);
    for(int i = 2;i < n + 1;++i)
    {
        scanf("%d", A + i);
        graph[A[i]].push_back(i);
    }

    dfs(1, -1, 0);

    int ans = 0;
    while(!q.empty())
    {
        int round = -q.top().first;
        int dep = -q.top().second.first;
        int node = q.top().second.second;
        q.pop();

        assert(B[node] and "BUGG!!");
        ans = max(ans, round);
        if(node == 1)
            --B[node];

        else
        {
            if(!B[A[node]])
            {
                ++B[A[node]];
                --B[node];
                q.push({-round - 1, {-d[A[node]], A[node]}});
            }
            else
                q.push({-round - 1, {-d[node], node}});
        }
    }

    printf("%d\n", ans);

    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:34:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
                    ^
./Main.cpp:38:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", A + i);
                           ^

Judge Result