Submission #503457

#	Time	Username	Problem	Language	Result	Execution time	Memory
503457		79brue	철도 요금 (JOI16_ho_t3)	C++14	100 / 100	190 ms	21444 KiB

2016_ho_t3

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

struct Edge{
    int s, e, x;
    Edge(){}
    Edge(int s, int e, int x): s(s), e(e), x(x){}
};

int n, m, q;
bool edgeValid[200002];
Edge arr[200002];
vector<Edge> link[200002];
int dist[200002];
int ans;
int indeg[200002];
bool edgeVisited[200002];

void bfs(){
    vector<bool> visited (n+10);
    visited[1] = 1;
    queue<int> que; que.push(1);
    while(!que.empty()){
        int x = que.front(); que.pop();
        for(auto y: link[x]){
            if(visited[y.e]) continue;
            visited[y.e] = 1;
            dist[y.e] = dist[y.s] + 1;
            que.push(y.e);
        }
    }

    for(int i=1; i<=n; i++){
        vector<Edge> vec;
        for(auto y: link[i]){
            if(dist[y.s] + 1 == dist[y.e]) vec.push_back(y);
        }
        link[i] = vec;
    }
}

int main(){
    scanf("%d %d %d", &n, &m, &q);
    for(int i=1; i<=m; i++){
        int x, y;
        scanf("%d %d", &x, &y);
        link[x].push_back(Edge(x, y, i));
        link[y].push_back(Edge(y, x, i));
        arr[i] = Edge(x, y, i);
        edgeValid[i] = 1;
    }
    bfs();
    for(int i=1; i<=m; i++){
        if(dist[arr[i].s] == dist[arr[i].e]) edgeValid[i] = 0;
        else{
            if(dist[arr[i].s] > dist[arr[i].e]) swap(arr[i].s, arr[i].e);
            indeg[arr[i].e]++;
        }
    }
    for(int i=1; i<=q; i++){
        int pnt;
        scanf("%d", &pnt);
        if(!edgeValid[pnt] || edgeVisited[pnt]){
            printf("%d\n", ans);
            continue;
        }

        queue<int> que;
        que.push(pnt);
        while(!que.empty()){
            int e = que.front(); que.pop();
            edgeVisited[e] = 1;
            indeg[arr[e].e]--;
            if(!indeg[arr[e].e]){
                ans++;
                for(Edge p: link[arr[e].e]){
                    if(edgeVisited[p.x]) continue;
                    que.push(p.x);
                }
            }
        }
        printf("%d\n", ans);
    }
}

Compilation message (stderr)

2016_ho_t3.cpp: In function 'int main()':
2016_ho_t3.cpp:46:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     scanf("%d %d %d", &n, &m, &q);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
2016_ho_t3.cpp:49:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~
2016_ho_t3.cpp:65:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |         scanf("%d", &pnt);
      |         ~~~~~^~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 14 / 14
• Subtask 3: 35 / 35
• Subtask 4: 39 / 39