Submission #942402

#	Time	Username	Problem	Language	Result	Execution time	Memory
942402		emad234	Dreaming (IOI13_dreaming)	C++17	100 / 100	70 ms	31836 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
#define ll long long
#define F first
#define S second
#define pii pair<int,int>
const int mod = 1e9 + 7;
const int mxN = 2e5 + 5;
using namespace std;
vector<vector<pii>>v;
vector<int>nums;
int mx[mxN];
bool vis[mxN];
int ans = 0;
int path;
int dpD[mxN],dpU[mxN];
void dfs(int u){
    vis[u] = 1;
    for(auto x : v[u]){
        if(vis[x.F]) continue;
        dfs(x.F);
        dpD[u] = max(dpD[x.F] + x.S,dpD[u]);
    }
}
void hfs(int u,int par){
    multiset<int>s;
    for(auto x : v[u]){
        if(x.F == par) continue;
        s.insert(dpD[x.F] + x.S);
    }
    for(auto x : v[u]){
        if(x.F == par) continue; 
        dpU[x.F] = dpU[u] + x.S;
        s.erase(s.find(dpD[x.F] + x.S));
        if(s.size()) dpU[x.F] = max(dpU[x.F], *(s.rbegin()) + x.S);
        s.insert(dpD[x.F] + x.S);
    }
    for(auto x : v[u]) if(x.F != par) hfs(x.F,u);
    path = min(path,max(dpD[u],dpU[u]));
    ans = max({ans,dpU[u],dpD[u]});
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    v.clear();
    v.resize(N + 2);
    for(int i = 0;i < M;i++){
        v[A[i]].push_back({B[i],T[i]});
        v[B[i]].push_back({A[i],T[i]});
    }
    for(int i = 0;i < N;i++){
        if(!vis[i]){
            path = 2e9;
            dfs(i);
            hfs(i,-1);
            nums.push_back(path + L);
        }
    }
    sort(nums.begin(),nums.end());
    nums[nums.size() - 1] -= L;
    sort(nums.begin(),nums.end());
    // for(auto x : nums) cout<<x<<' ';
    // cout<<'\n';
    for(int i = 0;i < nums.size();i++){
        int num = 0;
        if(i == nums.size() - 1){
            if(i != 0){
                num = nums[i] + nums[i - 1];
            }
        } else num = nums[i] + nums[nums.size() - 1];
        ans = max(num,ans);
    }
    return ans;
}

// #define MAX_N 100000

// static int A[MAX_N];
// static int B[MAX_N];
// static int T[MAX_N];

// int main() {
// 	int N, M, L, i;
// 	int res;
// 	cin >>N>>M>>L;
// 	for (i = 0; i < M; i++)
// 		cin>>A[i]>>B[i]>>T[i];

// 	int answer = travelTime(N, M, L, A, B, T);
// 	printf("%d\n", answer);
// 	return 0;
// }

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:62:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |     for(int i = 0;i < nums.size();i++){
      |                   ~~^~~~~~~~~~~~~
dreaming.cpp:64:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |         if(i == nums.size() - 1){
      |            ~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23