Submission #952504

#	Time	Username	Problem	Language	Result	Execution time	Memory
952504		hariaakas646	Pipes (CEOI15_pipes)	C++14	0 / 100	1646 ms	65536 KiB

pipes

#include <bits/stdc++.h>

using namespace std;

#define scd(t) scanf("%d", &t)
#define sclld(t) scanf("%lld", &t)
#define forr(i, j, k) for (int i = j; i < k; i++)
#define frange(i, j) forr(i, 0, j)
#define all(cont) cont.begin(), cont.end()
#define mp make_pair
#define pb push_back
#define f first
#define s second
typedef long long int lli;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<lli> vll;
typedef vector<string> vs;
typedef vector<pii> vii;
typedef vector<vi> vvi;
typedef map<int, int> mpii;
typedef set<int> seti;
typedef multiset<int> mseti;
typedef long double ld;


void usaco()
{
    freopen("/media/hariaakash646/785EF1075EF0BF46/CompetitiveProgramming/input.in", "r", stdin);
//    freopen("problem.out", "w", stdout);
}

vvi graph;
vi dis1, dis2;

int findf(int x, vi &dis) {
    if(x == dis[x]) return x;
    dis[x] = findf(dis[x], dis);
    return dis[x];
}

void unionf(int x, int y, vi &dis) {
    x = findf(x, dis);
    y = findf(y, dis);
    dis[y] = x;
}

vii bridg;
vi num, lowpt;
stack<pii> stk;
int timer=0;

void dfs(int x, int y) {
    num[y] = ++timer;
    lowpt[y] = num[y];
    for(auto e : graph[y]) {
        if(e == x) continue;
        if(num[e] && num[e] < num[y]) {
            lowpt[y] = min(lowpt[y], num[e]);
            stk.push(mp(y, e));
        }
        else if(!num[e]) {
            stk.push(mp(y, e));
            dfs(y, e);
            lowpt[y] = min(lowpt[y], lowpt[e]);
        }
    }

    if(x != 0 && lowpt[y] >= num[x]) {
        vii edg;
        while(stk.top() != mp(x, y)) {
            // printf("%d %d\n", stk.top().f, stk.top().s);
            edg.pb(stk.top());
            stk.pop();
        }
        // printf("%d %d\n", stk.top().f, stk.top().s);
        edg.pb(stk.top());
        
        stk.pop();
        // printf("*******************\n");
        if(edg.size() == 1) bridg.pb(edg[0]);
    }
}

int main() {
    // usaco();
    int n, m;
    scd(n);
    scd(m);
    graph = vvi(n+1);
    dis1 = dis2 = vi(n+1);

    forr(i, 1, n+1) {
        dis1[i] = dis2[i] = i;
    }

    frange(i, m) {
        int a, b;
        scd(a);
        scd(b);
        // if(findf(a, dis1) != findf(b, dis1)) {
        //     unionf(a, b, dis1);
        //     graph[a].pb(b);
        //     graph[b].pb(a);
        // }
        // else if(findf(a, dis2) != findf(b, dis2)) {
        //     unionf(a, b, dis2);
        //     graph[a].pb(b);
        //     graph[b].pb(a);
        // }
        graph[a].pb(b);
        graph[b].pb(a);
    }

    lowpt = num = vi(n+1);
    forr(i, 1, n+1) {
        if(!num[i]) dfs(0, i);
    }

    for(auto p : bridg) printf("%d %d\n", p.f, p.s);

}

Compilation message (stderr)

pipes.cpp: In function 'void usaco()':
pipes.cpp:30:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     freopen("/media/hariaakash646/785EF1075EF0BF46/CompetitiveProgramming/input.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pipes.cpp: In function 'int main()':
pipes.cpp:5:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | #define scd(t) scanf("%d", &t)
      |                ~~~~~^~~~~~~~~~
pipes.cpp:89:5: note: in expansion of macro 'scd'
   89 |     scd(n);
      |     ^~~
pipes.cpp:5:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | #define scd(t) scanf("%d", &t)
      |                ~~~~~^~~~~~~~~~
pipes.cpp:90:5: note: in expansion of macro 'scd'
   90 |     scd(m);
      |     ^~~
pipes.cpp:5:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | #define scd(t) scanf("%d", &t)
      |                ~~~~~^~~~~~~~~~
pipes.cpp:100:9: note: in expansion of macro 'scd'
  100 |         scd(a);
      |         ^~~
pipes.cpp:5:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | #define scd(t) scanf("%d", &t)
      |                ~~~~~^~~~~~~~~~
pipes.cpp:101:9: note: in expansion of macro 'scd'
  101 |         scd(b);
      |         ^~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10