Submission #768375

#	Time	Username	Problem	Language	Result	Execution time	Memory
768375		hgmhc	날다람쥐 (JOI14_ho_t4)	C++17	100 / 100	126 ms	17280 KiB

2014_ho_t4

#include <bits/stdc++.h>
#define rep(i,a,b) for (auto i = (a); i <= (b); ++i)
#define Mup(x,y) x = max(x,y)
#define mup(x,y) x = min(x,y)
#define all(x) begin(x),end(x)
#define per(i,a,b) for (auto i = (b); i >= (a); --i)
using namespace std;
using ll = long long;
using ii = pair<int,int>;
#define dbg(...) fprintf(stderr,__VA_ARGS__)

const ll INF = 1e18;
const int N = 1e5+3;
int n, m, x, h[N];
vector<ii> adj[N];
ll dist[N];

int main() {
    scanf("%d%d%d", &n, &m, &x);
    rep(i,1,n) scanf("%d", &h[i]);
    rep(i,1,m) {
        int u, v, t;
        scanf("%d%d%d", &u, &v, &t);
        if (h[u] >= t) adj[u].push_back({v,t});
        if (h[v] >= t) adj[v].push_back({u,t});
    }
    fill(dist,dist+N,INF);
    priority_queue<pair<ll,int>> pq;
    dist[1] = 0, pq.push({0,1});
    while (not empty(pq)) {
        auto [d,a] = pq.top(); pq.pop(), d=-d;
        if (dist[a] < d) continue;
        for (auto [b,w] : adj[a]) {
            if (dist[a] < x) {
                if (x-dist[a] >= w) {
                    if (dist[b] > max(dist[a]+w,0LL+x-h[b])) {
                        dist[b] = max(dist[a]+w,0LL+x-h[b]);
                        pq.push({-dist[b],b});
                    }
                } else {
                    if (dist[b] > dist[a]+w+w-(x-dist[a])) {
                        dist[b] = dist[a]+w+w-(x-dist[a]);
                        pq.push({-dist[b],b});
                    }
                }
            }
            else if (dist[b] > dist[a]+2*w) {
                dist[b] = dist[a]+2*w;
                pq.push({-dist[b],b});
            }
        }
    }
    if (dist[n] < x) printf("%lld", h[n]-(x-dist[n]) + dist[n]);
    else if (h[n]+dist[n] >= INF) puts("-1");
    else printf("%lld", h[n]+dist[n]);
}

Compilation message (stderr)

2014_ho_t4.cpp: In function 'int main()':
2014_ho_t4.cpp:19:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |     scanf("%d%d%d", &n, &m, &x);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~
2014_ho_t4.cpp:20:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     rep(i,1,n) scanf("%d", &h[i]);
      |                ~~~~~^~~~~~~~~~~~~
2014_ho_t4.cpp:23:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |         scanf("%d%d%d", &u, &v, &t);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 50 / 50