Submission #469682

#	Time	Username	Problem	Language	Result	Execution time	Memory
469682		MohamedAliSaidane	Robot (JOI21_ho_t4)	C++14	0 / 100	103 ms	18516 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef tuple<int,int,int> ti;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<ll> vll;
typedef pair<ld,ld> pld;
#define pb push_back
#define popb pop_back()
#define pf push_front
#define popf pop_front
#define ff first
#define ss second
#define MOD (int)(1e8)
#define INF (ll) (1e18)
#define all(v) (v).begin(),(v).end()
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);}
ld pointdist(ld x, ld y, ld point) { return ((x-point)*(y-point))/abs(x-y); }
//ld dist(ld x, ld y, ld a, ld b){ return sqrt((x-a)*(x-a) + (y-b)*(y-b)); }
const int nx[8] = {0, 0, 1, -1,1,1,-1,-1}, ny[8] = {1, -1, 0, 0,1,-1,1,-1}; //East, West, South, North+
////////////******SOLUTION******\\\\\\\\\\\

const int MAX_N = 1e5 + 4;
const int MAX_M = 2e5 + 4;
pll edges[MAX_N];
vector<pair<pll,int>> adj[MAX_N];
int n, m;
bool visited[MAX_N];
ll dist[MAX_N];
void dfs(int x)
{
    visited[x] = true;
    map<int,int> m;
    map<ll,ll> sm;
    for(auto e: adj[x])
    {
        int col = edges[e.ff.ss].ff;
        m[col] ++;
        sm[col] += edges[e.ff.ss].ss;
        if(visited[e.ff.ff])
            continue;
        dfs(e.ff.ff);
    }
    for(auto e: adj[x])
    {
        int col = edges[e.ff.ss].ff;
        if(m[col] == 1)
            e.ss = 1;
    }
}

ll dijkstra(int x)
{
    set<pll> pq;
    pq.insert({0,x});
    while(!pq.empty())
    {
        pll pr = *(pq.begin());
        ll node = pr.ss;
        ll d = pr.ff;
        pq.erase(pq.begin());
        dist[node] = d;
        visited[node] = true;
        if(node == n)
            return d;
        for(auto e: adj[node])
        {
            if(visited[e.ff.ff])
                continue;
            if(e.ss)
            {
                if(dist[e.ff.ff] > d)
                {
                    dist[e.ff.ff] = d;
                    pq.insert({d,e.ff.ff});
                }
            }
            else
            {
                if(dist[e.ff.ff] > d+edges[e.ff.ss].ss)
                {
                    dist[e.ff.ff] = d+edges[e.ff.ss].ss;
                    pq.insert({d+edges[e.ff.ss].ss,e.ff.ff});
                }
            }
        }
    }
    return 69;
}
int main()
{
	ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    cin >> n >> m;
    for(int i = 0; i <m; i ++)
    {
        ll a, b, c, p;
        cin >> a >> b >> c >> p;
        adj[a].pb({{b,i},0});
        adj[b].pb({{a,i},0});
        edges[i] = {c,p};
    }
    dfs(1);
    if(!visited[n])
    {
        cout << -1;
        exit(0);
    }
    memset(visited,false,sizeof(visited));
    for(int i = 2; i <=n; i ++)
        dist[i] = INF;
    dist[1] = 0;
    cout << dijkstra(1);
}
/*
Identify problem diagram: Brute force, Greedy, Dynamic Programming, Divide and Conquer
Reformulate the problem into something more theoretical
!!!!! IMPLICIT GRAPH ??????
!!!!! PAY ATTENTION TO THE CONSTRAINTS: DP nD ? BF ? BITMASKING ?
!!!!! SOLVE THE SUBTASKS FIRST: IT'S TOTALLY OK NOT TO SOLVE THE PROBLEM ENTIRELY
Search for multiple approaches: select the seemingly optimal one
Remember that you're the king of CP
Change your approach
Imagine Corner cases before submitting
Don't spend too much time on the problem: move on !
*/

Compilation message (stderr)

Main.cpp:26:1: warning: multi-line comment [-Wcomment]
   26 | ////////////******SOLUTION******\\\\\\\\\\\
      | ^

• Subtask 1: 0 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42