[pat 1003] Emergency

已過測試用例的java代碼如下

利用了dfs的思想.對於每條路,深度優先搜索其通往的道路.visited在遍歷中設置爲true,在遍歷此節點過後設置爲false

public class PAT1003 {

private static int shortestPath = Integer.MAX_VALUE;

private static int shortCount = 0;

private static int maxAmount = 0;

private static int destPos;

private static int[] teamCountArray;

private static int[][] roadLenArray;

private static boolean[] visited;

private static int cityCount;

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    cityCount = scanner.nextInt();
    int roadCount = scanner.nextInt();
    int currentPos = scanner.nextInt();
    destPos = scanner.nextInt();
    teamCountArray = new int[cityCount];
    visited = new boolean[cityCount];
    for (int i = 0; i < cityCount; i++) {
        teamCountArray[i] = scanner.nextInt();
    }
    roadLenArray = new int[cityCount][cityCount];
    for (int i = 0; i < cityCount; i++) {
        for (int j = 0; j < cityCount; j++) {
            roadLenArray[i][j] = -1;
        }
    }
    for (int i = 0; i < roadCount; i++) {
        int src = scanner.nextInt();
        int desc = scanner.nextInt();
        int len = scanner.nextInt();
        roadLenArray[src][desc] = len;
        roadLenArray[desc][src] = len;
    }
    for (int i = 0; i < cityCount; i++) {
        visited[i] = false;
    }
    visited[currentPos] = true;
    if(currentPos == destPos){
        System.out.println("1" + " " + teamCountArray[currentPos]);
    }else{
        dfs(currentPos, 0, teamCountArray[currentPos]);
        System.out.println(shortCount + " " + maxAmount);
    }
}

static void dfs(int start, int pathLen, int teamCount) {
    for (int i = 0; i < cityCount; i++) {
        if (roadLenArray[start][i] != -1) {
            if (i == destPos) {
                int newPathLen = pathLen + roadLenArray[start][i];
                int newTeamCount = teamCount + teamCountArray[i];
                if (newPathLen < shortestPath) {
                    maxAmount = newTeamCount;
                    shortCount = 1;
                    shortestPath = newPathLen;
                } else if (newPathLen == shortestPath) {
                    maxAmount = maxAmount > newTeamCount ? maxAmount : newTeamCount;
                    shortCount++;
                }
                visited[i] = false;
                continue;
            }
            if (!visited[i]) {
                //未遍歷過
                if (pathLen + roadLenArray[start][i] <= shortestPath) {
                    visited[i] = true;
                    dfs(i, pathLen + roadLenArray[start][i], teamCount + teamCountArray[i]);
                    visited[i] = false;
                }
            }
        }
    }
}

}