Submission #8866

#	Time	Username	Problem	Language	Result	Execution time	Memory
8866		dohyun0324	Beads and wires (APIO14_beads)	C++98	100 / 100	645 ms	31676 KiB

beads

#include<stdio.h>
#include<algorithm>
#include<vector>
#define M 200010
#define N -214748364
using namespace std;
vector<int>con[M];
vector<int>len[M];
int D1[M],D2[M],D3[M],D4[M],D5[M],D6[M];
int dap,p,w,sum,x,y,c,n,big,big1[5],p1,p2,p3,p4,ch[200010],anc[200010],arr[200010],dap2,dap3;
int max(int x,int y,int z)
{
    if(x>=y && x>=z) return x;
    if(y>=x && y>=z) return y;
    return z;
}
void pro_D1(int x)
{
    int i,big=0,sum=0,k;
    for(i=0;i<con[x].size();i++)
    {
        if(anc[x]==con[x][i]) continue;
        k=max(D5[con[x][i]],D3[con[x][i]]+len[x][i]);
        big=max(big,max(D1[con[x][i]],D2[con[x][i]])-k,max(D6[con[x][i]],D4[con[x][i]])+len[x][i]-k);
        D1[x]+=k; arr[i]=k;
    }
    D5[x]=D1[x]; D1[x]+=big;
}
void pro_D2(int x,int sw)
{
    int i;
    for(i=1;i<=4;i++) big1[i]=N;
    sum=D5[x];
    for(i=0;i<con[x].size();i++){
        if(anc[x]==con[x][i]) continue;
        w=big1[1]; big1[1]=max(big1[1],len[x][i]+D5[con[x][i]]-arr[i]);
        if(w!=big1[1]) p1=i;
    }
    for(i=0;i<con[x].size();i++){
        if(anc[x]==con[x][i] || p1==i) continue;
        w=big1[2]; big1[2]=max(big1[2],len[x][i]+D5[con[x][i]]-arr[i]);
        if(w!=big1[2]) p2=i;
    }
    for(i=0;i<con[x].size();i++){
        if(anc[x]==con[x][i]) continue;
        w=big1[3]; if(sw==1) big1[3]=max(big1[3],len[x][i]+D1[con[x][i]]-arr[i]);
        else big1[3]=max(big1[3],len[x][i]+D2[con[x][i]]-arr[i]);
        if(w!=big1[3]) p3=i;
    }
    for(i=0;i<con[x].size();i++){
        if(anc[x]==con[x][i] || p3==i) continue;
        w=big1[4]; if(sw==1) big1[4]=max(big1[4],len[x][i]+D1[con[x][i]]-arr[i]);
        else big1[4]=max(big1[4],len[x][i]+D2[con[x][i]]-arr[i]);
        if(w!=big1[4]) p4=i;
    }
    if((x==1 && con[x].size()<=1) || (x!=1 && con[x].size()<=2)) D2[x]=N;
    else{
        big=N;
        if(p1!=p3 && big<big1[1]+big1[3]) big=big1[1]+big1[3];
        if(p1!=p4 && big<big1[1]+big1[4]) big=big1[1]+big1[4];
        if(p2!=p3 && big<big1[2]+big1[3]) big=big1[2]+big1[3];
        if(p2!=p4 && big<big1[2]+big1[4]) big=big1[2]+big1[4];
        D2[x]=max(D2[x],sum+big);
    }
}
void pro_D3(int x)
{
    int i;
    sum=0;
    for(i=0;i<con[x].size();i++){
        if(anc[x]==con[x][i]) continue;
        sum+=max(D5[con[x][i]],D3[con[x][i]]+len[x][i]);
        arr[i]=max(D5[con[x][i]],D3[con[x][i]]+len[x][i]);
    }
    dap=N; dap2=N; dap3=N;
    for(i=0;i<con[x].size();i++){
        if(anc[x]==con[x][i]) continue;
        big=len[x][i]+D5[con[x][i]]-arr[i]; if(dap<big) dap=big;
        big=len[x][i]+D1[con[x][i]]-arr[i]; if(dap2<big) dap2=big;
        big=len[x][i]+D2[con[x][i]]-arr[i]; if(dap3<big) dap3=big;
    }
    D3[x]=dap+sum; D6[x]=dap2+sum; D4[x]=dap3+sum;
}
void dfs(int x)
{
    int i,j;
    ch[x]=1;
    for(i=0;i<con[x].size();i++){
        if(ch[con[x][i]]==1){anc[x]=con[x][i]; continue;}
        dfs(con[x][i]);
    }
    pro_D1(x); pro_D2(x,1); pro_D2(x,2); pro_D3(x);
    if(con[x].size()==1 && x!=1) D3[x]=N, D4[x]=N, D6[x]=N;
}
int main()
{
    int i;
    scanf("%d",&n);
    for(i=1;i<n;i++){
        scanf("%d %d %d",&x,&y,&c);
        con[x].push_back(y); con[y].push_back(x);
        len[x].push_back(c); len[y].push_back(c);
    }
    dfs(1);
    printf("%d",max(D1[1],D2[1]));
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'void pro_D1(int)':
beads.cpp:20:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++)
             ~^~~~~~~~~~~~~~
beads.cpp:19:17: warning: unused variable 'sum' [-Wunused-variable]
     int i,big=0,sum=0,k;
                 ^~~
beads.cpp: In function 'void pro_D2(int, int)':
beads.cpp:34:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp:39:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp:44:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp:50:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp: In function 'void pro_D3(int)':
beads.cpp:70:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp:76:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp: In function 'void dfs(int)':
beads.cpp:88:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<con[x].size();i++){
             ~^~~~~~~~~~~~~~
beads.cpp:86:11: warning: unused variable 'j' [-Wunused-variable]
     int i,j;
           ^
beads.cpp: In function 'int main()':
beads.cpp:98:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
beads.cpp:100:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d",&x,&y,&c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~

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