USACO 3.1 Agri-Net

#include <stdio.h>
#define DEBUG 1
#define TESTCASES 9
#define MAX_FARMS 100
#define INF 1e6
int distanceMatrix[MAX_FARMS + 1][MAX_FARMS + 1];
int distanceArray[MAX_FARMS + 1];
int visited[MAX_FARMS + 1];

int main(){
#if DEBUG
	int testCase;
	for (testCase = 1; testCase <= TESTCASES; testCase++){
		char inputFileName[20] = "inputx.txt";
		inputFileName[5] = '1' +  (testCase - 1);
		freopen(inputFileName, "r", stdin);
		printf("\n#%d\n", testCase);
#endif

	int numOfFarms;
	scanf("%d", &numOfFarms);

	int from, to;
	for (from = 1; from <= numOfFarms; from++)
		for (to = 1; to <= numOfFarms; to++)
			scanf("%d", &distanceMatrix[from][to]);
	
	int farm;
	for (farm = 1; farm <= numOfFarms; farm++){
		visited[farm] = 0;
		distanceArray[farm] = distanceMatrix[1][farm];
	}

	while (1){
		int nearestFarm = 0, minDistance = INF;
		for (farm = 1; farm <= numOfFarms; farm++)
			if (visited[farm] == 0 && distanceArray[farm] < minDistance){
				nearestFarm = farm;
				minDistance = distanceArray[farm];
			}
		if (minDistance == INF)
			break;
		visited[nearestFarm] = 1;
		for (farm = 1; farm <= numOfFarms; farm++)
			if (visited[farm] == 0 && distanceMatrix[nearestFarm][farm] < distanceArray[farm])
				distanceArray[farm] = distanceMatrix[nearestFarm][farm];
	}

	int result = 0;
	for (farm = 1; farm <= numOfFarms; farm++)
		result += distanceArray[farm];

	printf("%d\n", result);	

#if DEBUG
	}
#endif
	return 0;
}