Submission #79438

#	Time	Username	Problem	Language	Result	Execution time	Memory
79438		duality	Mousetrap (CEOI17_mousetrap)	C++11	100 / 100	1230 ms	169640 KiB

mousetrap

#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 ----------

int t,m;
vi adjList[1000000];
int parent[1000000],dp[1000000];
int doDFS(int u,int p) {
    int i;
    int m1 = 0,m2 = 0,c = 0;
    parent[u] = p;
    for (i = 0; i < adjList[u].size(); i++) {
        int v = adjList[u][i];
        if (v != p) {
            doDFS(v,u);
            if (dp[v] >= m1) m2 = m1,m1 = dp[v];
            else if (dp[v] >= m2) m2 = dp[v];
            c++;
        }
    }
    dp[u] = m2+c;
    return dp[u];
}
vi w[1000000];
int sum[1000000];
int main() {
    int i;
    int n;
    int a,b;
    scanf("%d %d %d",&n,&t,&m),t--,m--;
    for (i = 1; i < n; i++) {
        scanf("%d %d",&a,&b);
        a--,b--;
        adjList[a].pb(b);
        adjList[b].pb(a);
    }

    int j;
    int u = m,p = -1,c = 0;
    doDFS(t,-1);
    while (u != t) {
        for (i = 0; i < adjList[u].size(); i++) {
            int v = adjList[u][i];
            if ((v != parent[u]) && (v != p)) w[c].pb(dp[v]),sum[c]++;
        }
        sort(w[c].begin(),w[c].end(),greater<int>());
        p = u,u = parent[u],c++;
    }
    for (i = c-1; i >= 0; i--) sum[i] += sum[i+1];
    int l = 0,r = n;
    while (l < r) {
        int m = (l+r) / 2;
        int used = 0,can = 0;
        for (i = 0; i < c; i++) {
            can++,p = used;
            for (j = 0; j < w[i].size(); j++) {
                if (w[i][j]+sum[i]+p > m) {
                    used++,can--;
                    if (can < 0) break;
                }
            }
            if (j < w[i].size()) break;
        }
        if ((i == c) && (used <= m)) r = m;
        else l = m+1;
    }
    printf("%d\n",l);

    return 0;
}

Compilation message (stderr)

mousetrap.cpp: In function 'int doDFS(int, int)':
mousetrap.cpp:65:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~
mousetrap.cpp: In function 'int main()':
mousetrap.cpp:95:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (i = 0; i < adjList[u].size(); i++) {
                     ~~^~~~~~~~~~~~~~~~~~~
mousetrap.cpp:109:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (j = 0; j < w[i].size(); j++) {
                         ~~^~~~~~~~~~~~~
mousetrap.cpp:115:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if (j < w[i].size()) break;
                 ~~^~~~~~~~~~~~~
mousetrap.cpp:83:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d",&n,&t,&m),t--,m--;
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
mousetrap.cpp:85:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 25 / 25
• Subtask 3: 20 / 20
• Subtask 4: 35 / 35