Submission #1014076

#	Time	Username	Problem	Language	Result	Execution time	Memory
1014076		ZanP	Dreaming (IOI13_dreaming)	C++17	Compilation error	0 ms	0 KiB

dreaming

#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
const int mxN = 1e6;
const int INF = 1e9;
int n, m, l;
vector<pair<int, int>> pov[mxN];
int td[mxN];
bool vis[mxN];
int maxd = 0, cnt = 0;
pair<int, int> dfs(int u, int par) {
    pair<int, int> ans = { 0,u };
    vis[u] = true;
    for (auto p : pov[u]) {
        int v = p.first;
        int c = p.second;
        if (v != par) {
            pair<int, int> q = dfs(v, u);
            q.first += c;
            ans = max(ans, q);
        }
    }
    return ans;
}

int opt = INF;
int opt_dfs(int u, int tar, int d, int par)
{
    if (u == tar) {
        opt = d;
        return d;
    }
    int ans = INF;
    for (auto p : pov[u]) {
        int v = p.first;
        int c = p.second;
        if (v != par) {
            int dis = opt_dfs(v, tar, d, u) - c;
            ans = min(ans, dis);
        }
    }
    opt = min(max(ans,d-ans), opt);
    return ans;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    int n = N; int m = M; int l = L;
    for (int i = 0; i < m; i++) {
        int a = A[i], b = B[i], c = T[i];
        pov[a].push_back({ b,c });
        pov[b].push_back({ a,c });
    }
    memset(vis, 0, n);
    for (int i = 0; i < n; i++) {
        if (!vis[i] && pov[i].size() <= 1) {
            pair<int, int> p = dfs(i, -1);
            pair<int, int> q = dfs(p.second, -1);
            maxd = q.first;
            opt = INF;
            opt_dfs(p.second, q.second, q.first, -1);
            td[cnt] = opt;
            cnt++;
        }
    }
    if (cnt == 1) {
        return maxd;
    }
    sort(td, td + cnt, isgreater<int,int>);
    int ans = l + td[0] + td[1];
    if (cnt > 2) { ans = max(ans, 2 * l + td[1] + td[2]); }
    return ans;
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:70:24: error: 'isgreater' was not declared in this scope
   70 |     sort(td, td + cnt, isgreater<int,int>);
      |                        ^~~~~~~~~
dreaming.cpp:70:34: error: expected primary-expression before 'int'
   70 |     sort(td, td + cnt, isgreater<int,int>);
      |                                  ^~~
dreaming.cpp:70:38: error: expected primary-expression before 'int'
   70 |     sort(td, td + cnt, isgreater<int,int>);
      |                                      ^~~