Submission #356295

#	Time	Username	Problem	Language	Result	Execution time	Memory
356295		parsabahrami	Senior Postmen (BOI14_postmen)	C++17	55 / 100	608 ms	78148 KiB

postmen

// Call my Name and Save me from The Dark
#include <bits/stdc++.h>
 
using namespace std;

typedef long long int ll;
typedef pair<int, int> pii;
 
#define SZ(x)                       (int) x.size()
#define F                           first
#define S                           second

const int N = 5e5 + 10;
int P[N], R[N], L[N], M[N], ptr[N], from[N], to[N], n, m; vector<int> adj[N], tr; 

void tour(int v) {
    while (ptr[v] < SZ(adj[v])) {
        int id = adj[v][ptr[v]++]; int u = from[id] ^ v ^ to[id];
        if (!M[id]) M[id] = 1, tour(u);
    }
    tr.push_back(v);
}

int Find(int v) {
    return !~P[v] ? v : P[v] = Find(P[v]);
}

void Union(int u, int v) {
    u = Find(u), v = Find(v);
    if (u == v) return;
    if (L[u] > L[v]) swap(u, v);
    P[u] = v, L[v] = L[v] + L[u], R[v] = max(R[u], R[v]);
}

int main() {
    memset(P, -1, sizeof P);
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= m; i++) {
        scanf("%d%d", &from[i], &to[i]);
        adj[from[i]].push_back(i);
        adj[to[i]].push_back(i);
    }
    tour(1);
    for (int i = 0; i <= SZ(tr); i++) L[i] = 1, R[i] = i;
    memset(M, -1, sizeof M);
    for (int i = 0; i < SZ(tr) && L[Find(0)] != SZ(tr); i = R[Find(i + 1)]) {
        //printf("i %d\n", i);
        if (~M[tr[i]]) {
            int l = M[tr[i]];
            for (int j = M[tr[i]]; j < i; j = R[Find(j + 1)]) {
                //printf("j %d\n", j);
                printf("%d ", tr[j]), M[tr[j]] = -1;
            }
            printf("\n");
            for (int j = l; j < i; j = R[Find(j + 1)]) {
                Union(j, R[Find(j + 1)]);
            }
            M[tr[i]] = i;
        } else M[tr[i]] = i;
    }
    return 0;
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:37:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   37 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
postmen.cpp:39:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   39 |         scanf("%d%d", &from[i], &to[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 0 / 45