Submission #479972

#	Time	Username	Problem	Language	Result	Execution time	Memory
479972		Yuisuyuno	Robot (JOI21_ho_t4)	C++14	100 / 100	1053 ms	87644 KiB

Main

//Nguyen Huu Hoang Minh
#include <bits/stdc++.h>
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define reset(x) memset(x, 0,sizeof(x))
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define N 2005
#define remain(x) if (x > MOD) x -= MOD
#define ii pair<int, int>
#define iiii pair< ii , ii >
#define viiii vector< iiii >
#define vi vector<int>
#define vii vector< ii >
#define bit(x, i) (((x) >> (i)) & 1)
#define Task "test"
#define int long long

using namespace std;

typedef long double ld;
const int inf = 1e10;
const int minf = -1e10;

int n, m;
struct edge{
    int to, c, p;
};
map<int, vector<edge>> g[100005];
int d[100005];
map<int,int> d2[100005], psum[100005];

void readfile()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    if (fopen(Task".inp","r"))
    {
        freopen(Task".inp","r",stdin);
        //freopen(Task".out","w",stdout);
    }
    cin >> n >> m;
    for(int i=1; i<=m; i++){
        int u, v, z, p;
        cin >> u >> v >> z >> p;
        g[u][z].pb({v,z,p});
        g[v][z].pb({u,z,p});
        psum[u][z]+=p;
        psum[v][z]+=p;
    }
}

void proc()
{
    memset(d, 0x3f, sizeof d);
    d[1]=0;
    priority_queue<tuple<int,int,int>> q;
    q.push({0,1,0});
    while (q.size()){
        int cost, node, c;
        tie(cost,node,c) = q.top();
        q.pop();
        if (c){
            if (d2[node][c]!=-cost) continue;
            for(edge i : g[node][c]){
                int case1 = psum[node][c]-i.p-cost;
                if (case1 < d[i.to]){
                    d[i.to] = case1;
                    q.push({-d[i.to],i.to,0});
                }
            }
        }
        else {
			if (d[node] != -cost) continue;
			for (auto& i : g[node]) {
				for (edge j : i.second) {
					// Case 1: We don't flip j
					int case1 = psum[node][j.c] - j.p - cost;
					if (case1 < d[j.to]) {
						d[j.to] = case1;
						q.push({-d[j.to], j.to, 0});
					}
					// Case 2: We flip j but not another edge of the same colour
					int case2 = j.p - cost;
					if (case2 < d[j.to]) {
						d[j.to] = case2;
						q.push({-d[j.to], j.to, 0});
					}
					// Case 3: We flip j and another edge of the same colour
					int case3 = -cost;
					if (!d2[j.to].count(j.c) || case3 < d2[j.to][j.c]) {
						d2[j.to][j.c] = case3;
						q.push({-d2[j.to][j.c], j.to, j.c});
					}
				}
			}
		}
    }
    cout << (d[n] > 1e18 ? -1 : d[n]);
}

signed main()
{
    readfile();
    proc();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void readfile()':
Main.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen(Task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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