HDU 1688 Sightseeing

#include <stdio.h>
#define MAX_CITIES 1000
#define MAX_ROADS 10000
#define INF 1000000

int numOfCities, numOfRoads;
typedef struct Road{
int to;
int len;
int next;
}Road;
Road RoadArray[MAX_ROADS + 1];
int RoadNum;
int head[MAX_CITIES + 1];
int start, final;
int dist[MAX_CITIES + 1][2];
int count[MAX_CITIES + 1][2];
int visited[MAX_CITIES + 1][2];

int main(){

int testCases;
scanf("%d", &testCases);
while (testCases--){
scanf("%d%d", &numOfCities, &numOfRoads);

int i;
for (i = 1; i <= numOfCities; i++){
visited[i][0] = visited[i][1] = 0;
dist[i][0] = dist[i][1] = INF;
head[i] = 0;
}

RoadNum = 0;
int from, to, len;
for (i = 1; i <= numOfRoads; i++){
scanf("%d%d%d", &from, &to, &len);
RoadNum++;
RoadArray[RoadNum].to = to;
RoadArray[RoadNum].len = len;
RoadArray[RoadNum].next = head[from];
head[from] = RoadNum;
}

scanf("%d%d", &start, &final);

dist[start][0] = 0;
count[start][0] = 1;

int doubleCities = numOfCities << 1;

for (i = 1; i <= doubleCities; i++){
int distance = INF;
int city = 0;
int zeroOrOne;
int j;
for (j = 1; j <= numOfCities; j++){
if (visited[j][0] == 0 && dist[j][0] < distance){
distance = dist[j][0];
city = j;
zeroOrOne = 0;
} else if (visited[j][1] == 0 && dist[j][1] < distance){
distance = dist[j][1];
city = j;
zeroOrOne = 1;
}
}

if (city == 0){
break;
}

visited[city][zeroOrOne] = 1;

for (j = head[city]; j != 0; j = RoadArray[j].next){
to = RoadArray[j].to;
int newDist = distance + RoadArray[j].len;

if (newDist < dist[to][0]){
dist[to][1] = dist[to][0];
count[to][1] = count[to][0];

dist[to][0] = newDist;
count[to][0] = count[city][zeroOrOne];
} else if (newDist == dist[to][0]){
count[to][0] += count[city][zeroOrOne];
} else if (newDist < dist[to][1]){
dist[to][1] = newDist;
count[to][1] = count[city][zeroOrOne];
} else if (newDist == dist[to][1]){
count[to][1] += count[city][zeroOrOne];
}
}
}

int num = count[final][0];
if (dist[final][1] - 1 == dist[final][0]){
num += count[final][1];
}
printf("%d\n", num);
}
return 0;
}