Submission #206070

#	Time	Username	Problem	Language	Result	Execution time	Memory
206070		PeppaPig	Designated Cities (JOI19_designated_cities)	C++14	9 / 100	431 ms	31236 KiB

designated_cities

#include <bits/stdc++.h>

#define long long long
#define pii pair<long, long>
#define x first
#define y second

using namespace std;

const int N = 2e5+5;

struct Edge {
    int v;
    long c, d;
    Edge(int v, long c, long d) : v(v), c(c), d(d) {}
};

int n, q, rot, deg[N];
vector<Edge> g[N];

long dwn[N], ans[N];

void pre_process(int u, int p) {
    for(Edge v : g[u]) if(v.v != p) {
        pre_process(v.v, u);
        dwn[u] += v.c + dwn[v.v];
    }
}

void dfs(int u, int p, long sum) {
    ans[1] = min(ans[1], sum);
    for(Edge v : g[u]) if(v.v != p) {
        sum -= v.c, sum += v.d;
        dfs(v.v, u, sum);
        sum += v.c, sum -= v.d;
    }
}

int main() {
    ans[1] = 1e18;

    scanf("%d", &n);
    for(int i = 1, a, b, c, d; i < n; i++) {
        scanf("%d %d %d %d", &a, &b, &c, &d);
        g[a].emplace_back(b, c, d);
        g[b].emplace_back(a, d, c);
        ++deg[a], ++deg[b];
    }
    for(int i = 1; i <= n; i++) if(deg[i] != 1) rot = i;
    pre_process(rot, 0), dfs(rot, 0, dwn[rot]);

    priority_queue<pii, vector<pii>, greater<pii> > Q;
    for(int i = 1; i <= n; i++) if(deg[i] == 1)
        Q.emplace(g[i][0].d, i);

    while(Q.size() > 2) {
        pii now = Q.top(); Q.pop();
        int u = now.y; long dist = now.x;
        int nex = -1;
        for(Edge v : g[u]) if(deg[v.v] > 1) {
            --deg[v.v];
            if(deg[v.v] == 1) nex = v.v;
            else ans[Q.size()] = ans[Q.size() + 1] + dist;
        }
        if(nex != -1) for(Edge v : g[nex]) if(deg[v.v] > 1)
            Q.emplace(dist + v.d, nex);
    }

    scanf("%d", &q);
    for(int i = 1, a; i <= q; i++) {
        scanf("%d", &a);
        printf("%lld\n", ans[a]);
    }

    return 0;
}

Compilation message (stderr)

designated_cities.cpp: In function 'int main()':
designated_cities.cpp:42:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
designated_cities.cpp:44:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d %d", &a, &b, &c, &d);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
designated_cities.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &q);
     ~~~~~^~~~~~~~~~
designated_cities.cpp:71:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &a);
         ~~~~~^~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 7
• Subtask 3: 9 / 9
• Subtask 4: 0 / 17
• Subtask 5: 0 / 17
• Subtask 6: 0 / 44