Submission #81785

#	Time	Username	Problem	Language	Result	Execution time	Memory
81785		tjdgus4384	두 로봇 (KOI18_robot)	C++14	100 / 100	111 ms	56968 KiB

robot

#include<cstdio>
#include<vector>
#include<queue>
#include<string.h>
#include<algorithm>
#define INF 1000000000
using namespace std;
vector<pair<int, int> > v[100001];
int dist[100001];
pair<int, int> pa[100001];


int main()
{
    int n, s, e, a, b, c;
    scanf("%d %d %d", &n, &s, &e);
    for(int i = 1;i < n;i++)
    {
        scanf("%d %d %d", &a, &b, &c);
        v[a].push_back({b, c});
        v[b].push_back({a, c});
    }
    if(s == e)
    {
        printf("0");
        return 0;
    }
    priority_queue<pair<int, pair<int, pair<int, int> > >, vector<pair<int, pair<int, pair<int, int> > > >, greater<pair<int, pair<int, pair<int, int> > > > > pq;
    fill(dist, dist + n + 1, INF);
    pq.push({0, {s, {s, 0}}});
    dist[s] = 0;
    bool visited[100001] = {0};
    while(!pq.empty())
    {
        int curr, prev, d;
        do{
            curr = pq.top().second.first;
            prev = pq.top().second.second.first;
            d = pq.top().second.second.second;
            pq.pop();
        } while(!pq.empty() && visited[curr]);
        visited[curr] = true;
        pa[curr] = {prev, d};
        for(int i = 0;i < v[curr].size();i++)
        {
            int next = v[curr][i].first;
            int d = v[curr][i].second;
            if(dist[next] > dist[curr] + d)
            {
                dist[next] = dist[curr] + d;
                pq.push({dist[next], {next, {curr, d}}});
            }
        }
    }
    int x = e, m = 0;
    while(x != pa[x].first)
    {
        m = max(m, pa[x].second);
        x = pa[x].first;
    }
    printf("%d", dist[e] - m);
}

Compilation message (stderr)

robot.cpp: In function 'int main()':
robot.cpp:44:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0;i < v[curr].size();i++)
                       ~~^~~~~~~~~~~~~~~~
robot.cpp:16:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &n, &s, &e);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
robot.cpp:19:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &a, &b, &c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 19 / 19
• Subtask 3: 23 / 23
• Subtask 4: 41 / 41