HDU 1688 Sightseeing

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