【noip模拟题】藏宝图（prim）

#include <cstdio>
#include <cstring>
#include <cmath>
#include <string>
#include <iostream>
#include <algorithm>
#include <queue>
#include <set>
#include <vector>
#include <map>
using namespace std;
typedef long long ll;
#define pii pair<int, int>
#define mkpii make_pair<int, int>
#define pdi pair<double, int>
#define mkpdi make_pair<double, int>
#define pli pair<ll, int>
#define mkpli make_pair<ll, int>
#define rep(i, n) for(int i=0; i<(n); ++i)
#define for1(i,a,n) for(int i=(a);i<=(n);++i)
#define for2(i,a,n) for(int i=(a);i<(n);++i)
#define for3(i,a,n) for(int i=(a);i>=(n);--i)
#define for4(i,a,n) for(int i=(a);i>(n);--i)
#define CC(i,a) memset(i,a,sizeof(i))
#define read(a) a=getint()
#define print(a) printf("%d", a)
#define dbg(x) cout << (#x) << " = " << (x) << endl
#define error(x) (!(x)?puts("error"):0)
#define printarr2(a, b, c) for1(_, 1, b) { for1(__, 1, c) cout << a[_][__]; cout << endl; }
#define printarr1(a, b) for1(_, 1, b) cout << a[_] << ‘\t‘; cout << endl
inline const ll getint() { ll r=0, k=1; char c=getchar(); for(; c<‘0‘||c>‘9‘; c=getchar()) if(c==‘-‘) k=-1; for(; c>=‘0‘&&c<=‘9‘; c=getchar()) r=r*10+c-‘0‘; return k*r; }
inline const int max(const int &a, const int &b) { return a>b?a:b; }
inline const int min(const int &a, const int &b) { return a<b?a:b; }

const int N=2505, oo=~0u>>1;
int n, vis[N], from[N], ihead[N], cnt;
ll sum[N], child[N], mp[N][N], mp2[N][N], d[N];
struct dat { int next, to; ll w; }e[N<<1];
priority_queue<pli, vector<pli>, greater<pli> >q;
void add(int u, int v, ll w) {
	e[++cnt].next=ihead[u]; ihead[u]=cnt; e[cnt].to=v; e[cnt].w=w;
	e[++cnt].next=ihead[v]; ihead[v]=cnt; e[cnt].to=u; e[cnt].w=w;
}
void prim() {
	for1(i, 1, n) d[i]=oo;
	d[1]=0; q.push(mkpli(0, 1));
	while(!q.empty()) {
		int u=q.top().second; q.pop(); if(vis[u]) continue; vis[u]=1;
		for1(v, 1, n) if(!vis[v] && mp[u][v] && d[v]>mp[u][v]) {
			d[v]=mp[u][v];
			from[v]=u;
			q.push(mkpli(d[v], v));
		}
	}
	for1(i, 2, n) if(d[i]!=oo) add(from[i], i, d[i]);
}
void dfs(int x, int fa) {
	for1(i, 1, n) if(vis[i]) mp2[i][x]=mp2[x][i]=mp2[i][fa]+mp2[fa][x];
	int y; child[x]=0; sum[x]=0; vis[x]=1;
	for(int i=ihead[x]; i; i=e[i].next) if((y=e[i].to)!=fa) {
		mp2[x][y]=mp2[y][x]=e[i].w;
		dfs(y, x);
		sum[y]+=e[i].w;
		sum[x]+=e[i].w;
		child[y]++;
		child[x]++;
	}
}
void init() {
	for1(i, 1, n) vis[i]=ihead[i]=from[i]=child[i]=sum[i]=0;
	for1(i, 1, n) for1(j, 1, n) mp2[i][j]=mp[i][j]=0;
	cnt=0;
	while(!q.empty()) q.pop();
}
int main() {
	int cs=getint();
	while(cs--) {
		read(n); if(n==1) { puts("Yes"); puts("1"); n=getint(); continue; }
		init();
		int flag=0;

		for1(i, 1, n) for1(j, 1, n) read(mp[i][j]);
		prim();
		for1(i, 1, n) if(d[i]==oo) { puts("No"); flag=1; break; }
		if(flag) continue;

		for1(i, 1, n) vis[i]=0;
		dfs(1, 0);

		//for1(i, 1, n) { for1(j, 1, n) printf("%d ", mp2[i][j]); puts(""); }
		for1(i, 1, n) { for1(j, 1, n) if(mp2[i][j]!=mp[i][j]) { flag=1; break; } if(flag) break; }
		if(!flag) {
			double mx=-1e199; int ans;
			// for1(i, 1, n) dbg(sum[i]);
			// for1(i, 1, n) dbg(child[i]);
			for1(i, 1, n) if((double)sum[i]/(double)child[i]>mx) { mx=sum[i]/child[i]; ans=i; }
			printf("Yes\n%d\n", ans);
		}
		else puts("No");
	}
	return 0;
}