Submission #525277

#	Time	Username	Problem	Language	Result	Execution time	Memory
525277		qwerasdfzxcl	Mountains and Valleys (CCO20_day1problem3)	C++14	Compilation error	0 ms	0 KiB

Main

#include <bits/stdc++.h>

typedef long long ll;
using namespace std;
struct Edge{
    int v, w, i;
    Edge(){}
    Edge(int _v, int _w, int _i): v(_v), w(_w), i(_i) {}
};
vector<Edge> adj[500500];
int on[2002000], W[2002000], dist[500500];
vector<Edge> E;

vector<int> P;
bool dfs0(int s, int e, int pa = -1){
    if (s==e) return 1;
    for (auto &v:adj[s]) if (v.v!=pa && on[v.i]){
        P.push_back(v.i);
        if (dfs0(v.v, e, s)) return 1;
        P.pop_back();
    }
    return 0;
}

int visited[500500], tm;
void dfs(int s, int pa = -1, int w = 0){
    visited[s] = tm;
    if (pa==-1) dist[s] = 0;
    else dist[s] = dist[pa] + w;
    for (auto &v:adj[s]) if (v.v!=pa && on[v.i]) dfs(v.v, s, v.w);
}

int cur = 0, ans = 1e9, m;
int calc(int s, int n){
    fill(dist, dist+n, 0);
    dfs(s);
    if (*max_element(dist, dist+n)==0) return 0;

    dfs(max_element(dist, dist+n)-dist);

    return *max_element(dist, dist+n);
}

int main(){
    int n;
    scanf("%d %d", &n, &m);
    for (int i=1;i<=m;i++){
        int x, y, z;
        scanf("%d %d %d", &x, &y, &z);
        adj[x].emplace_back(y, z, i);
        adj[y].emplace_back(x, z, i);
        W[i] = z;

        if (z==1) on[i] = 1, cur++;
        else E.emplace_back(x, y, i);
    }

    ans = min(ans, cur*2 - calc(0, n));

    if (n>500) {printf("%d\n", ans); return 0;}

    for (auto &e:E){
        //printf(" %d %d\n", e.v, e.w);
        P.clear();
        assert(dfs0(e.v, e.w));

        on[e.i] = 1, cur += W[e.i];

        int tval = 1e9;
        for (auto &x:P){
            on[x] = 0, cur -= W[x];
            ans = min(ans, cur*2 - calc(0, n));
            tval = min(tval, cur*2 - calc(0, n));
            on[x] = 1, cur += W[x];
        }

        ///cycle
        on[e.i] = 0;
        vector<int> deep;

        int len = W[e.i] + P.size();

        for (auto &x:P) on[x] = 0;

        tm++;
        for (int i=0;i<n;i++) if (visited[i]!=tm){
            ans = min(ans, cur*2-len-calc(i, n));
        }
        ///

        for (auto &x:P) on[x] = 1;

        on[e.i] = 0, cur -= W[e.i];
    }

    printf("%d\n", ans);
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void dfs(int, int, int)':
Main.cpp:27:18: error: reference to 'tm' is ambiguous
   27 |     visited[s] = tm;
      |                  ^~
In file included from /usr/include/time.h:39,
                 from /usr/include/c++/10/ctime:42,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:49,
                 from Main.cpp:1:
/usr/include/x86_64-linux-gnu/bits/types/struct_tm.h:7:8: note: candidates are: 'struct tm'
    7 | struct tm
      |        ^~
Main.cpp:25:22: note:                 'int tm'
   25 | int visited[500500], tm;
      |                      ^~
Main.cpp: In function 'int main()':
Main.cpp:85:9: error: reference to 'tm' is ambiguous
   85 |         tm++;
      |         ^~
In file included from /usr/include/time.h:39,
                 from /usr/include/c++/10/ctime:42,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:49,
                 from Main.cpp:1:
/usr/include/x86_64-linux-gnu/bits/types/struct_tm.h:7:8: note: candidates are: 'struct tm'
    7 | struct tm
      |        ^~
Main.cpp:25:22: note:                 'int tm'
   25 | int visited[500500], tm;
      |                      ^~
Main.cpp:86:47: error: reference to 'tm' is ambiguous
   86 |         for (int i=0;i<n;i++) if (visited[i]!=tm){
      |                                               ^~
In file included from /usr/include/time.h:39,
                 from /usr/include/c++/10/ctime:42,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:49,
                 from Main.cpp:1:
/usr/include/x86_64-linux-gnu/bits/types/struct_tm.h:7:8: note: candidates are: 'struct tm'
    7 | struct tm
      |        ^~
Main.cpp:25:22: note:                 'int tm'
   25 | int visited[500500], tm;
      |                      ^~
Main.cpp:46:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
Main.cpp:49:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         scanf("%d %d %d", &x, &y, &z);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~