Submission #6637717

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Source Code Expand

// luogu-judger-enable-o2
/*
Problem : luogu AT2134
Algorithm : MST
Status :
*/
#include <bits/stdc++.h>
#include <cstring>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <iostream>
using namespace std;
typedef long long ll;

const int INF = 0x3f3f3f3f;
const int MAXN = 2e5 + 5;

int n,m,tot,cnt;
ll ans;
int d[MAXN],f[MAXN];

struct Edge{
	int u,v,w;
} e[MAXN * 2];

bool cmp(const Edge &x,const Edge &y){
	return x.w < y.w;
}

void add(int u,int v,int w){
	e[++tot].u = u;
	e[tot].v = v;
	e[tot].w = w;
}

int find(int x){
	if(x == f[x])
	    return x;
	else
	    return f[x] = find(f[x]);
}

int main(){
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int i = 0;i <= n;i++){
		f[i] = i;
		d[i] = INF;
	}
	for(int i = 1;i <= m;i++){
		int a,b,c;
		scanf("%d%d%d",&a,&b,&c);
		add(a,b,c);
		d[a] = min(d[a],c + 1);
		d[b] = min(d[b],c + 2);
	}
	for(int i = 0;i < n;i++)
	    d[i] = min(d[i],d[(i - 1 + n) % n] + 2);
	for(int i = 0;i < n;i++)
	    d[i] = min(d[i],d[(i - 1 + n) % n] + 2);
	for(int i = 0;i < n;i++)
	    add(i,(i + 1) % n,d[i]);
	sort(e + 1,e + 1 + tot,cmp);
	for(int i = 1;i <= tot;i++){
		int x = e[i].u;
		int y = e[i].v;
		if(find(x) != find(y)){
			f[find(x)] = find(y);
			ans += e[i].w;
			cnt++;
			if(cnt == n - 1)
			    break;
		}
	}
	printf("%lld\n",ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:47:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^
./Main.cpp:54:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d",&a,&b,&c);
                           ^

Judge Result