Submission #78654

#	Time	Username	Problem	Language	Result	Execution time	Memory
78654		duality	007 (CEOI14_007)	C++11	100 / 100	358 ms	17604 KiB

007

#define DEBUG 0

#include <bits/stdc++.h>
using namespace std;

#if DEBUG
// basic debugging macros
int __i__,__j__;
#define printLine(l) for(__i__=0;__i__<l;__i__++){cout<<"-";}cout<<endl
#define printLine2(l,c) for(__i__=0;__i__<l;__i__++){cout<<c;}cout<<endl
#define printVar(n) cout<<#n<<": "<<n<<endl
#define printArr(a,l) cout<<#a<<": ";for(__i__=0;__i__<l;__i__++){cout<<a[__i__]<<" ";}cout<<endl
#define print2dArr(a,r,c) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<a[__i__][__j__]<<" ";}cout<<endl;}
#define print2dArr2(a,r,c,l) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<setw(l)<<setfill(' ')<<a[__i__][__j__]<<" ";}cout<<endl;}

// advanced debugging class
// debug 1,2,'A',"test";
class _Debug {
    public:
        template<typename T>
        _Debug& operator,(T val) {
            cout << val << endl;
            return *this;
        }
};
#define debug _Debug(),
#else
#define printLine(l)
#define printLine2(l,c)
#define printVar(n)
#define printArr(a,l)
#define print2dArr(a,r,c)
#define print2dArr2(a,r,c,l)
#define debug
#endif

// define
#define MAX_VAL 999999999
#define MAX_VAL_2 999999999999999999LL
#define EPS 1e-6
#define mp make_pair
#define pb push_back

// typedef
typedef unsigned int UI;
typedef long long int LLI;
typedef unsigned long long int ULLI;
typedef unsigned short int US;
typedef pair<int,int> pii;
typedef pair<LLI,LLI> plli;
typedef vector<int> vi;
typedef vector<LLI> vlli;
typedef vector<pii> vpii;
typedef vector<plli> vplli;

// ---------- END OF TEMPLATE ----------

vi adjList[200000];
int dist1[200000],dist2[200000];
int visited[200000],m;
int doDFS(int u) {
    if (visited[u]) return 0;
    int i;
    visited[u] = 1;
    m = min(m,dist1[u]);
    for (i = 0; i < adjList[u].size(); i++) {
        int v = adjList[u][i];
        if ((dist1[v] == dist2[v]) && (dist1[v] < dist1[u])) doDFS(v);
    }
    return 0;
}
queue<int> Q;
int main() {
    int i;
    int N,M;
    int s,d,a,b,u,v;
    scanf("%d %d",&N,&M);
    scanf("%d %d %d %d",&s,&d,&a,&b);
    s--,d--,a--,b--;
    for (i = 0; i < M; i++) {
        scanf("%d %d",&u,&v);
        u--,v--;
        adjList[u].pb(v);
        adjList[v].pb(u);
    }

    fill(dist1,dist1+N,-1);
    dist1[a] = 0;
    Q.push(a);
    while (!Q.empty()) {
        u = Q.front();
        Q.pop();

        for (i = 0; i < adjList[u].size(); i++) {
            v = adjList[u][i];
            if (dist1[v] == -1) {
                dist1[v] = dist1[u]+1;
                Q.push(v);
            }
        }
    }
    fill(dist2,dist2+N,-1);
    dist2[b] = 0;
    Q.push(b);
    while (!Q.empty()) {
        u = Q.front();
        Q.pop();

        for (i = 0; i < adjList[u].size(); i++) {
            v = adjList[u][i];
            if (dist2[v] == -1) {
                dist2[v] = dist2[u]+1;
                Q.push(v);
            }
        }
    }
    int ans = max(min(dist1[d]-dist1[s],dist2[d]-dist2[s]),-1);
    if (dist1[s] != dist2[s]) {
        if (dist1[s] < dist2[s]) {
            if (dist2[d] == ans+dist1[s]) ans--;
        }
        else {
            if (dist1[d] == ans+dist2[s]) ans--;
        }
        printf("%d\n",max(ans,-1));
    }
    else {
        if (dist1[d] != dist2[d]) printf("%d\n",ans);
        else {
            m = N,doDFS(s);
            int t = m;
            if (!visited[d]) {
                m = N,doDFS(d);
                if (m < t) ans--;
            }
            printf("%d\n",max(ans,-1));
        }
    }

    return 0;
}

Compilation message (stderr)

007.cpp: In function 'int doDFS(int)':
007.cpp:66:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~
007.cpp: In function 'int main()':
007.cpp:94:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (i = 0; i < adjList[u].size(); i++) {
                     ~~^~~~~~~~~~~~~~~~~~~
007.cpp:109:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (i = 0; i < adjList[u].size(); i++) {
                     ~~^~~~~~~~~~~~~~~~~~~
007.cpp:77:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&N,&M);
     ~~~~~^~~~~~~~~~~~~~~
007.cpp:78:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d %d",&s,&d,&a,&b);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
007.cpp:81:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&u,&v);
         ~~~~~^~~~~~~~~~~~~~~

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