我嘞个最大生成树

#include <iostream>
#include <cstdio>
#include <memory.h>
#define int long long
using namespace std;
int a[2005][2005];
int dis[2005];
bool vis[2005];
int n, m, x, y, len, add = 3e9, mod = 1e9 + 7;
int peruyimu(){
	for(int i = 2; i <= n; i++){
		dis[i] = a[1][i];
	}
	int ct = 0;
	vis[1] = 1;
	for(int i = 2; i <= n; i++){
		int mx = 0, idx = -1;
		for(int j = 2; j <= n; j++){
			if(!vis[j] && mx < dis[j]){
				mx = dis[j], idx = j;
			}
		}
		if(idx == -1) return -1;
		vis[idx] = 1;
		ct += dis[idx];
		for(int j = 2; j <= n; j++) dis[j] = max(dis[j], a[idx][j]);
	}
	return ct;
}
int read(){
	char c = getchar();
	int x = 0, f = 1;
	while(!isdigit(c)){
		if(c == '-') f = -f;
		c = getchar();
	}
	while(isdigit(c)){
		x = (x << 3) + (x << 1) + c - '0';
		c = getchar();
	}
	return x * f;
}
signed main(){
	memset(a, 63, sizeof(a));
	n = read();
	for(int i = 1; i <= n; i++){
        for(int j = 1; j <= n; j++) a[i][j] = read();
	}
    cout << peruyimu();

	return 0;
}