Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

const (
	MAX_N      = 200
	MAX_WEIGHT = 2000
)

type Edge struct {
	start  int
	end    int
	weight int
}

type ShortestInfo struct {
	edges    []Edge
	shortest int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	shortestList := make([]ShortestInfo, n)
	for i := 1; i < n; i++ {
		shortestList[i] = ShortestInfo{edges: []Edge{}, shortest: MAX_N*MAX_WEIGHT + 1}
	}

	adjacentMatrix := make([][]int, n)
	for i := 0; i < n; i++ {
		adjacentMatrix[i] = make([]int, n)
		for j := 0; j < n; j++ {
			v, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjacentMatrix[i][j] = v
		}
	}

	mst([]int{1}, shortestList, adjacentMatrix)
	fmt.Println(calculateMinWeight(shortestList))
}

func calculateMinWeight(shortestList []ShortestInfo) int {
	visitedList := make([]bool, len(shortestList))
	visitedList[0] = true
	sumWeight := 0
	for !visitedAll(visitedList) {
		shortestInfo := shortestList[0]
		shortestList = shortestList[1:]
		edges := shortestInfo.edges
		for _, edge := range edges {
			if !visitedList[edge.end-1] {
				visitedList[edge.end-1] = true
				sumWeight += edge.weight
			}
		}
	}
	return sumWeight
}

func visitedAll(visitedList []bool) bool {
	for _, v := range visitedList {
		if !v {
			return false
		}
	}
	return true
}

func mst(nodeStack []int, shortestList []ShortestInfo, adjacentMatrix [][]int) {
	for len(nodeStack) > 0 {
		currentNode := nodeStack[0]
		nodeStack = nodeStack[1:]
		currentShortest := getShortest(currentNode, shortestList)
		adjacents := findAdjacents(currentNode, adjacentMatrix)
		for i := 0; i < len(adjacents); i++ {
			adj := adjacents[i]
			s := getShortest(adj.end, shortestList)
			if currentShortest.shortest+adj.weight < s.shortest || (currentShortest.shortest+adj.weight == s.shortest && len(currentShortest.edges)+1 > len(s.edges)) {
				setShortest(adj.end, adj, currentShortest, shortestList)
				nodeStack = append(nodeStack, adj.end)
			}
		}
	}
}

func getShortest(node int, shortestList []ShortestInfo) ShortestInfo {
	return shortestList[node-1]
}

func setShortest(node int, edge Edge, currentShortest ShortestInfo, shortestList []ShortestInfo) {
	newEdges := make([]Edge, len(currentShortest.edges)+1)
	for i := 0; i < len(newEdges)-1; i++ {
		newEdges[i] = currentShortest.edges[i]
	}
	newEdges[len(newEdges)-1] = edge
	shortestInfo := ShortestInfo{edges: newEdges, shortest: currentShortest.shortest + edge.weight}
	shortestList[node-1] = shortestInfo
}

func findAdjacents(currentNode int, adjacentMatrix [][]int) []Edge {
	adjacents := adjacentMatrix[currentNode-1]
	edges := []Edge{}
	for i, v := range adjacents {
		if v > 0 {
			edges = append(edges, Edge{start: currentNode, end: i + 1, weight: v})
		}
	}
	return edges
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <cstdio>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;

template <class T>
using gp_queue=priority_queue<T, deque<T>, less<T>>;

using Weight=int;
using DArray=vector<Weight>;
using DMatrix=vector<DArray>;

static const Weight INF=1<<29;

struct Edge {
    size_t src, dst;
    Weight weight;
    Edge() {}
    Edge(size_t src, size_t dst, Weight weight=1):
        src(src), dst(dst), weight(weight)
    {}
};

bool operator<(const Edge &e, const Edge &f) {
    if (e.weight != f.weight) {
        return e.weight > f.weight;
    } else {
        return e.src!=f.src? e.src<f.src : e.dst<f.dst;
    }
}

using Edges=vector<Edge>;
using Vertex=vector<Edge>;
using Graph=vector<Vertex>;

void join(Graph &g, size_t s, size_t d, Weight w=1) {
    // non-directed
    g[s].push_back(Edge(s, d, w));
    g[d].push_back(Edge(d, s, w));
}

void connect(Graph &g, size_t s, size_t d, Weight w=1) {
    // directed
    g[s].push_back(Edge(s, d, w));
}

struct UnionFindTree {
    size_t n;
    vector<int> tree;
    UnionFindTree(size_t n): n(n) {
        tree = vector<int>(n, -1);
    }
    int find_root(size_t v) {
        if (tree[v] < 0) return v;
        return tree[v] = find_root(tree[v]);
    }
    bool unite(size_t x, size_t y) {
        x = find_root(x);
        y = find_root(y);
        if (x == y) return false;
        if (rank(x) < rank(y)) swap(x, y);
        tree[x] += tree[y];
        tree[y] = x;
        return true;
    }
    bool has_same_root(size_t x, size_t y) {
        return find_root(x) == find_root(y);
    }
    size_t rank(size_t v) {
        return -tree[find_root(v)];
    }
};

pair<Weight, Edges> minimum_spanning_forest(const Graph &g) {
    /* Kruskal */
    size_t V=g.size();
    UnionFindTree tree(V);
    gp_queue<Edge> q;
    for (size_t u=0; u<V; ++u)
        for (const Edge &e: g[u])
            if (u < e.dst) q.push(e);

    Weight total=0;
    Edges F;
    while (F.size()<V-1 && !q.empty()) {
        Edge e=q.top(); q.pop();
        if (tree.unite(e.src, e.dst)) {
            F.push_back(e);
            total += e.weight;
        }
    }

    return make_pair(total, F);
}

int main() {
    size_t n;
    scanf("%zu", &n);

    Graph g(n);
    for (size_t i=0; i<n; ++i)
        for (size_t j=0; j<n; ++j) {
            Weight a;
            scanf("%d", &a);

            if (a > -1)
                connect(g, i, j, a);
        }

    printf("%d\n", minimum_spanning_forest(g).first);
    return 0;
}