Submission #171012

#	Time	Username	Problem	Language	Result	Execution time	Memory
171012		PeppaPig	Toll (APIO13_toll)	C++14	100 / 100	2226 ms	16344 KiB

toll

#include <bits/stdc++.h>

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

using namespace std;

const int N = 1e5+5;

int dsu[N];

void init() { iota(dsu, dsu + N, 0); }

int find(int x) { return dsu[x] = x == dsu[x] ? x : find(dsu[x]); }

int n, m, k;
long ans;
vector<iii> E, sure, cmp;
vector<pii> toll;
vector<int> g[25];

int cid[N], sz[N];
int par[25], dep[25], weight[25], chk[25];
long csz[25], subsz[25];

void dfs(int u, int p) {
    par[u] = p, dep[u] = dep[p] + 1;
    for(int v : g[u]) if(v != p) {
        dfs(v, u);
        subsz[u] += subsz[v];
    }
}

int main() {
    scanf("%d %d %d", &n, &m, &k);
    for(int i = 1, a, b, c; i <= m; i++) {
        scanf("%d %d %d", &a, &b, &c);
        E.emplace_back(c, a, b);
    }

    sort(E.begin(), E.end());
    init();
    vector<iii> mst_edge;
    for(iii e : E) {
        int a, b, c; tie(c, a, b) = e;
        if(find(a) != find(b)) {
            dsu[find(a)] = find(b);
            mst_edge.emplace_back(e);
        }
    }
    swap(E, mst_edge);

    init();
    for(int i = 1, a, b; i <= k; i++) {
        scanf("%d %d", &a, &b);
        toll.emplace_back(a, b);
        dsu[find(a)] = find(b);
    }
    for(int i = 1; i <= n; i++) scanf("%d", sz + i);
    for(iii e : E) {
        int a, b, c; tie(c, a, b) = e;
        if(find(a) != find(b)) {
            dsu[find(a)] = find(b);
            sure.emplace_back(e);
        } else cmp.emplace_back(e);
    }

    init();
    for(iii e : sure) {
        int a, b, c; tie(c, a, b) = e;
        dsu[find(a)] = find(b);
    }
    int ptr = 0;
    for(int i = 1; i <= n; i++) if(find(i) == i)
        cid[i] = ++ptr;
    for(int i = 1; i <= n; i++) if(find(i) != i)
        cid[i] = cid[find(i)];
    for(int i = 1; i <= n; i++)
        csz[cid[i]] += sz[i];

    for(int bit = 0; bit < (1 << k); bit++) {
        memset(chk, 0, sizeof chk);
        for(int i = 1; i <= ptr; i++) {
            g[i].clear();
            subsz[i] = csz[i];
            dsu[i] = i;
        }

        bool valid = true;
        for(int i = 0; i < k; i++) if(bit >> i & 1) {
            int a = toll[i].x, b = toll[i].y;
            if(find(cid[a]) == find(cid[b])) {
                valid = false;
                break;
            } else {
                g[cid[a]].emplace_back(cid[b]);
                g[cid[b]].emplace_back(cid[a]);
                dsu[find(cid[a])] = find(cid[b]);
            }
        }
        if(!valid) continue;
        for(int i = 0; i < cmp.size(); i++) {
            int a, b, c; tie(c, a, b) = cmp[i];
            if(find(cid[a]) != find(cid[b])) {
                g[cid[a]].emplace_back(cid[b]);
                g[cid[b]].emplace_back(cid[a]);
                dsu[find(cid[a])] = find(cid[b]);
                chk[i] = true;
            }
        }
        dfs(cid[1], 0);

        for(int i = 0; i < cmp.size(); i++) if(chk[i]) {
            int a, b, c; tie(c, a, b) = cmp[i];
            if(par[cid[b]] == cid[a]) swap(a, b);
            weight[cid[a]] = 0;
        }
        for(int i = 0; i < k; i++) if(bit >> i & 1) {
            int a, b; tie(a, b) = toll[i];
            if(par[cid[b]] == cid[a]) swap(a, b);
            weight[cid[a]] = 1e9;
        }

        for(int i = 0; i < cmp.size(); i++) if(!chk[i]) {
            int a = get<1>(cmp[i]), b = get<2>(cmp[i]), c = get<0>(cmp[i]);
            a = cid[a], b = cid[b];
            if(dep[a] < dep[b]) swap(a, b);

            while(dep[a] > dep[b]) {
                weight[a] = min(weight[a], c);
                a = par[a];
            }
            while(a != b) {
                weight[a] = min(weight[a], c);
                weight[b] = min(weight[b], c);
                a = par[a], b = par[b];
            }
        }

        long ret = 0;
        for(int i = 1; i <= ptr; i++) ret += 1ll * weight[i] * subsz[i];
        ans = max(ans, ret);
    }
    printf("%lld\n", ans);

    return 0;
}

Compilation message (stderr)

toll.cpp: In function 'int main()':
toll.cpp:105:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < cmp.size(); i++) {
                        ~~^~~~~~~~~~~~
toll.cpp:116:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < cmp.size(); i++) if(chk[i]) {
                        ~~^~~~~~~~~~~~
toll.cpp:127:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < cmp.size(); i++) if(!chk[i]) {
                        ~~^~~~~~~~~~~~
toll.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &n, &m, &k);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
toll.cpp:40:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &a, &b, &c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
toll.cpp:58:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~
toll.cpp:62:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 1; i <= n; i++) scanf("%d", sz + i);
                                 ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 18 / 18
• Subtask 3: 22 / 22
• Subtask 4: 22 / 22
• Subtask 5: 22 / 22