Submission #49592

#	Time	Username	Problem	Language	Result	Execution time	Memory
49592		mohammad_kilani	Duathlon (APIO18_duathlon)	C++17	0 / 100	120 ms	14324 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define oo 200000000
const int N = 100010;
const int M = 100010;
int n , m ,comp[N] , num[N] , comp_cnt = 0 , u , v  , dfs_cnt = 0 , dfs_low[N] , dfs_num[N] , num1[N] , num2[N] ;
bool vis[N] ; 
long long all = 0 , ans = 0;
vector< int > g[N] ; 

void DFS1(int node){
    comp[node] = comp_cnt;
    num[comp_cnt]++;
    vis[node] = true;
    for(int i=0;i<g[node].size();i++){
        if(vis[g[node][i]] == false)
            DFS1(g[node][i]);
    }
}

void DFS(int node, int prnt){
    dfs_low[node] = dfs_num[node] = dfs_cnt++;
    num1[node] = 1;
    num2[node] = 1;
    vis[node] = true;
    for(int i=0;i<g[node].size();i++){
        if(g[node][i] == prnt) continue;
        if(vis[g[node][i]]){
            dfs_low[node] = min(dfs_low[node],dfs_num[g[node][i]]);
            continue;
        }
        DFS(g[node][i],node);
        dfs_low[node] = min(dfs_low[node],dfs_low[g[node][i]]);
        num1[node] += num1[g[node][i]];
        if(dfs_low[g[node][i]] == dfs_num[node]){
            ans += (long long)num2[g[node][i]] * (num2[g[node][i]] + 1) * (num2[g[node][i]] - 1);
            all -= (long long)num2[g[node][i]] * (num2[g[node][i]] + 1) * (num2[g[node][i]] - 1) / 6;
            ans += (long long)(num[comp[node]] - (1 + num1[g[node][i]])) * num1[g[node][i]] * 2;
            all -= (long long)(num[comp[node]] - (1 + num1[g[node][i]])) * num1[g[node][i]];
        }   
        else if(dfs_low[g[node][i]] < dfs_num[node]){
            num2[node] += num2[g[node][i]];
        }
        else{
            ans += (long long)(num[comp[node]] - (1 + num1[g[node][i]])) * num1[g[node][i]] * 2;
            all -= (long long)(num[comp[node]] - (1 + num1[g[node][i]])) * num1[g[node][i]];
        }
    }
}

int main() {
    scanf("%d%d",&n,&m);
    for(int i=0;i<m;i++){
        scanf("%d%d",&u,&v);
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for(int i=1;i<=n;i++){
        if(vis[i] == false){
            DFS1(i);
            all += (long long)num[comp_cnt] * (num[comp_cnt] - 1) * (num[comp_cnt] - 2) / 6;
            comp_cnt++;
        }
    }
    memset(vis,0,sizeof(vis));
    for(int i=1;i<=n;i++){
        if(vis[i] == false)
            DFS(i,-1);
    }
    ans += (long long)all * 4;
    cout << ans << endl;
    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void DFS1(int)':
count_triplets.cpp:16:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[node].size();i++){
                 ~^~~~~~~~~~~~~~~
count_triplets.cpp: In function 'void DFS(int, int)':
count_triplets.cpp:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<g[node].size();i++){
                 ~^~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int main()':
count_triplets.cpp:53:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
count_triplets.cpp:55:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&u,&v);
         ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10