Submission #145548

#	Time	Username	Problem	Language	Result	Execution time	Memory
145548		surface03	비용 (KOI11_cost)	C++14	24 / 24	57 ms	4088 KiB

cost

#include<bits/stdc++.h>
using namespace std;
using LL=long long;
const LL MOD=(int)1e9;
const int LM=(int)1e5+1;
int N,M,G[LM],cnt[LM];
LL sum,ans;
struct data{
    int s,e,w;
    bool operator<(const data&r)const{
        return w>r.w;
    }
}A[LM];
void input(){
    scanf("%d%d",&N,&M);
    for(int i=1;i<=N;i++){
        G[i]=i;
        cnt[i]=1;
    }
    for(int i=0;i<M;i++){
        scanf("%d%d%d",&A[i].s,&A[i].e,&A[i].w);
        sum+=A[i].w;
    }
    sort(A,A+M);
}
int Find(int n){
    if(G[n]==n)return n;
    return G[n]=Find(G[n]);
}
void Union(int s,int e){
    s=Find(s),e=Find(e);
    if(s==e)return;
    ans=(ans+sum*cnt[s]*cnt[e])%MOD;
    G[s]=e;
    cnt[e]+=cnt[s];
}
int main(){
    input();
    for(int i=0;i<M;i++){
        Union(A[i].s,A[i].e);
        sum-=A[i].w;
    }
    printf("%lld\n",ans);
}

Compilation message (stderr)

cost.cpp: In function 'void input()':
cost.cpp:15:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&N,&M);
     ~~~~~^~~~~~~~~~~~~~
cost.cpp:21:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d",&A[i].s,&A[i].e,&A[i].w);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4.8 / 4.8
• Subtask 2: 7.2 / 7.2
• Subtask 3: 12 / 12