Submission #31319

#	Time	Username	Problem	Language	Result	Execution time	Memory
31319		imaxblue	Pipes (BOI13_pipes)	C++14	100 / 100	383 ms	21352 KiB

pipes

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mp make_pair
#define pb push_back
#define x first
#define y second
#define pii pair<int, int>
#define p3i pair<pii, int>
#define pll pair<ll, ll>
#define p3l pair<pll, ll>
#define lseg L, (L+R)/2, N*2+1
#define rseg (L+R)/2+1, R, N*2+2
#define ub upper_bound
#define lb lower_bound
#define pq priority_queue
#define MN 1000000007
#define fox(zqfmgb, x) for (int zqfmgb=0; zqfmgb<x; ++zqfmgb)
#define fox1(zqfmgb, x) for (int zqfmgb=1; zqfmgb<=x; ++zqfmgb)
#define foxr(zqfmgb, x) for (int zqfmgb=x-1; zqfmgb>=0; --zqfmgb)
#define fox1r(zqfmgb, x) for (int zqfmgb=x; zqfmgb>0; --zqfmgb)
#define ms multiset
#define flood(x) memset(x, 0x3f3f3f3f, sizeof x)
#define drain(x) memset(x, 0, sizeof x)

int n, m, a, b, N, C;
int c[100005], f[500005], k;
int in[100005], u[100005];
vector<pii> v[100005], s;
queue<int> q;
bool F;
void dfs(int N, int P){
    //cout << N << ' ' << C << endl;
    if (u[N]){
        //cout << "*" << endl;
        if (u[N]==C || F){
            cout << 0 << endl;
            exit(0);
        }
        F=1;
        s.pb(mp(N, -1));
        fox(l, s.size()-1){
            c[s[l+1].x]-=c[s[l].x];
            f[s[l].y]+=c[s[l].x];
            c[s[l].x]=0;
            //cout << s[l].x << ' ' << s[l].y << ' ' << f[s[l].y] << endl;
        }
        k=c[s[0].x]/2;
        fox(l, s.size()-1){
            f[s[l].y]+=k;
            k*=-1;
        }
        s.pop_back();
        return;
    }

    u[N]=C;
    fox(l, v[N].size()){
        if (in[v[N][l].x]==0 || v[N][l].x==P) continue;
        if (P==-1 && u[v[N][l].x]) continue;
        C=3-C;
        s.pb(mp(N, v[N][l].y));
        dfs(v[N][l].x, N);
        s.pop_back();
        C=3-C;
    }
}
int main(){
    scanf("%i%i", &n, &m);
    fox1(l, n) scanf("%i", &c[l]);
    fox(l, m){
        scanf("%i%i", &a, &b);
        v[a].pb(mp(b, l));
        v[b].pb(mp(a, l));
        in[a]++; in[b]++;
    }
    fox1(l, n){
        if (in[l]==1) q.push(l);
    }
    while(!q.empty()){
        N=q.front(); q.pop();
        if (in[N]!=1) continue;
        in[N]--;
        fox(l, v[N].size()){
            if (in[v[N][l].x]==0) continue;
            c[v[N][l].x]-=c[N];
            f[v[N][l].y]=c[N];
            //cout << N << ' ' << v[N][l].y << ' ' << c[N] << endl;
            in[v[N][l].x]--;
            if (in[v[N][l].x]==1) q.push(v[N][l].x);
        }
    }
    fox1(l, n){
        if (in[l]==0 || u[l]) continue;
        C=1; F=0;
        dfs(l, -1);
    }
    for (int l=0; l<m; ++l){
        f[l]*=2;
        printf("%i\n", f[l]);
    }
    return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'void dfs(int, int)':
pipes.cpp:18:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(zqfmgb, x) for (int zqfmgb=0; zqfmgb<x; ++zqfmgb)
                                                 ^
pipes.cpp:42:9: note: in expansion of macro 'fox'
         fox(l, s.size()-1){
         ^
pipes.cpp:18:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(zqfmgb, x) for (int zqfmgb=0; zqfmgb<x; ++zqfmgb)
                                                 ^
pipes.cpp:49:9: note: in expansion of macro 'fox'
         fox(l, s.size()-1){
         ^
pipes.cpp:18:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(zqfmgb, x) for (int zqfmgb=0; zqfmgb<x; ++zqfmgb)
                                                 ^
pipes.cpp:58:5: note: in expansion of macro 'fox'
     fox(l, v[N].size()){
     ^
pipes.cpp: In function 'int main()':
pipes.cpp:18:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(zqfmgb, x) for (int zqfmgb=0; zqfmgb<x; ++zqfmgb)
                                                 ^
pipes.cpp:84:9: note: in expansion of macro 'fox'
         fox(l, v[N].size()){
         ^
pipes.cpp:69:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%i%i", &n, &m);
                          ^
pipes.cpp:70:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     fox1(l, n) scanf("%i", &c[l]);
                                  ^
pipes.cpp:72:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%i%i", &a, &b);
                              ^

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70