Submission #61849

#	Time	Username	Problem	Language	Result	Execution time	Memory
61849		duality	Beads and wires (APIO14_beads)	C++11	100 / 100	211 ms	19564 KiB

beads

#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 ----------

vpii adjList[200000];
int dp[200000][4];
int doDFS(int u,int p) {
    int i;
    int m = -MAX_VAL,m2 = -MAX_VAL,m3 = 0;
    for (i = 0; i < adjList[u].size(); i++) {
        int v = adjList[u][i].first,w = adjList[u][i].second;
        if (v != p) {
            doDFS(v,u);
            dp[u][2] += max(dp[v][3]+w,dp[v][2]);
            m = max(m,dp[v][2]+w-max(dp[v][3]+w,dp[v][2]));
            m2 = max(m2,dp[v][0]+w-max(dp[v][3]+w,dp[v][2]));
            m3 = max(m3,max(dp[v][0],dp[v][1]+w)-max(dp[v][3]+w,dp[v][2]));
        }
    }
    dp[u][3] = dp[u][2]+m,dp[u][1] = dp[u][2]+m2;
    m = m2 = -MAX_VAL;
    int mi = -1;
    for (i = 0; i < adjList[u].size(); i++) {
        int v = adjList[u][i].first,w = adjList[u][i].second;
        if (v != p) {
            int d = dp[v][0]+w-max(dp[v][3]+w,dp[v][2]);
            if (d >= m) m2 = m,m = d,mi = i;
            else if (d >= m2) m2 = d;
        }
    }
    for (i = 0; i < adjList[u].size(); i++) {
        int v = adjList[u][i].first,w = adjList[u][i].second;
        if (v != p) {
            int d = dp[v][2]+w-max(dp[v][3]+w,dp[v][2]);
            if (i == mi) m3 = max(m3,d+m2);
            else m3 = max(m3,d+m);
        }
    }
    dp[u][0] = dp[u][2]+m3;
    return 0;
}
int main() {
    int i;
    int n;
    int a,b,c;
    scanf("%d",&n);
    for (i = 1; i < n; i++) {
        scanf("%d %d %d",&a,&b,&c);
        a--,b--;
        adjList[a].pb(mp(b,c));
        adjList[b].pb(mp(a,c));
    }
    doDFS(0,-1);
    printf("%d\n",dp[0][0]);

    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'int doDFS(int, int)':
beads.cpp:63:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~
beads.cpp:76:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~
beads.cpp:84:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:99:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
beads.cpp:101:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d",&a,&b,&c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 15 / 15
• Subtask 3: 29 / 29
• Subtask 4: 43 / 43