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Submission #31633

# Submission time Handle Problem Language Result Execution time Memory
31633 2017-08-30T04:45:44 Z ngkan146 Beads and wires (APIO14_beads) C++
100 / 100
 222 ms 21096 KB 
#include <bits/stdc++.h>
using namespace std;
struct edge{
    int v,w;
    edge(int v=0,int w=0): v(v), w(w) {}
};
int n;
vector <edge> G[200005];
int dp[200005][5];
inline int val1(int pos,int w){
    return dp[pos][0] + w;
}
inline int val02(int pos,int w){
    return max(dp[pos][0], dp[pos][2] + w);
}
void dfs(int u,int p){
    for(int i=0;i<G[u].size();i++){
        int v = G[u][i].v;
        if (v == p) continue;
        dfs(v,u);
    }

    // dp[i][0]

    dp[u][0] = 0;
    for(int i=0;i<G[u].size();i++){
        int v = G[u][i].v;
        if (v == p) continue;
        dp[u][0] += val02(v,G[u][i].w);
    }

    // dp[i][1]

    int fi02=0,se02=0,fiva02=-(int)1e9, seva02=-(int)1e9;
    for(int i=0;i<G[u].size();i++){
        int v = G[u][i].v;
        int w = G[u][i].w;
        if (v == p) continue;
        if (val1(v,w) - val02(v,w) >= val1(fi02,fiva02) - val02(fi02,fiva02))
            se02 = fi02,
            seva02 = fiva02,
            fi02 = v,
            fiva02 = w;
        else if (val1(v,w) - val02(v,w) >= val1(se02,seva02) - val02(se02,seva02))
            se02 = v,
            seva02 = w;
    }
    dp[u][1] = - (int) 1e9;
    for(int i=0;i<G[u].size();i++){
        int v = G[u][i].v;
        int w = G[u][i].w;
        if (v == p) continue;
        dp[u][1] = max(dp[u][1], dp[u][0] - val02(v,w) + dp[v][1]);
        dp[u][1] = max(dp[u][1], dp[u][0] - val02(v,w) + dp[v][3] + w);
        if (v != fi02)
            dp[u][1] = max(dp[u][1], dp[u][0] - val02(v,w) + dp[v][1] + w - val02(fi02,fiva02) + dp[fi02][0] + fiva02);
        else if (se02)
            dp[u][1] = max(dp[u][1], dp[u][0] - val02(v,w) + dp[v][1] + w - val02(se02,seva02) + dp[se02][0] + seva02);
    }
    if (se02)
        dp[u][1] = max(dp[u][1], dp[u][0] - val02(fi02,fiva02) - val02(se02,seva02) + val1(fi02,fiva02) + val1(se02,seva02));

    // dp[i][2]

    dp[u][2] = -(int)1e9;
    for(int i=0;i<G[u].size();i++){
        int v = G[u][i].v;
        int w = G[u][i].w;
        if (v == p) continue;
        dp[u][2] = max(dp[u][2], dp[u][0] - val02(v,w) + dp[v][0] + G[u][i].w);
    }

    // dp[i][3]

    dp[u][3] = -(int)1e9;
    for(int i=0;i<G[u].size();i++){
        int v = G[u][i].v;
        int w = G[u][i].w;
        if (v == p) continue;
        dp[u][3] = max(dp[u][3], dp[u][0] - val02(v,w) + dp[v][1] + G[u][i].w);
    }
}
int main(){
    scanf("%d",&n);
    for(int i=1;i<n;i++){
        int x,y,w;
        scanf("%d %d %d",&x,&y,&w);
        G[x].push_back(edge(y,w));
        G[y].push_back(edge(x,w));
    }
    dfs(1,1);
    cout << max(dp[1][0], dp[1][1]);
}

Compilation message

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:17:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<G[u].size();i++){
                 ~^~~~~~~~~~~~
beads.cpp:26:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<G[u].size();i++){
                 ~^~~~~~~~~~~~
beads.cpp:35:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<G[u].size();i++){
                 ~^~~~~~~~~~~~
beads.cpp:49:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<G[u].size();i++){
                 ~^~~~~~~~~~~~
beads.cpp:66:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<G[u].size();i++){
                 ~^~~~~~~~~~~~
beads.cpp:76:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<G[u].size();i++){
                 ~^~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:84:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
beads.cpp:87:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d",&x,&y,&w);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 5 ms 4992 KB Output is correct
3 Correct 5 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 4992 KB Output is correct
8 Correct 5 ms 4992 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 4992 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 4992 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 5 ms 4992 KB Output is correct
3 Correct 5 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 4992 KB Output is correct
8 Correct 5 ms 4992 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 4992 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 4992 KB Output is correct
13 Correct 6 ms 4992 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 5 ms 4992 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 4992 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 5 ms 4992 KB Output is correct
3 Correct 5 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 4992 KB Output is correct
8 Correct 5 ms 4992 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 4992 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 4992 KB Output is correct
13 Correct 6 ms 4992 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 5 ms 4992 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 4992 KB Output is correct
23 Correct 8 ms 5376 KB Output is correct
24 Correct 8 ms 5376 KB Output is correct
25 Correct 9 ms 5376 KB Output is correct
26 Correct 12 ms 5632 KB Output is correct
27 Correct 12 ms 5632 KB Output is correct
28 Correct 11 ms 5632 KB Output is correct
29 Correct 11 ms 5632 KB Output is correct
30 Correct 11 ms 5632 KB Output is correct
31 Correct 11 ms 6016 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 5 ms 4992 KB Output is correct
3 Correct 5 ms 4992 KB Output is correct
4 Correct 6 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 4992 KB Output is correct
8 Correct 5 ms 4992 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 4992 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 4992 KB Output is correct
13 Correct 6 ms 4992 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 5 ms 4992 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 4992 KB Output is correct
23 Correct 8 ms 5376 KB Output is correct
24 Correct 8 ms 5376 KB Output is correct
25 Correct 9 ms 5376 KB Output is correct
26 Correct 12 ms 5632 KB Output is correct
27 Correct 12 ms 5632 KB Output is correct
28 Correct 11 ms 5632 KB Output is correct
29 Correct 11 ms 5632 KB Output is correct
30 Correct 11 ms 5632 KB Output is correct
31 Correct 11 ms 6016 KB Output is correct
32 Correct 41 ms 7852 KB Output is correct
33 Correct 40 ms 7896 KB Output is correct
34 Correct 36 ms 7800 KB Output is correct
35 Correct 195 ms 16504 KB Output is correct
36 Correct 214 ms 16440 KB Output is correct
37 Correct 196 ms 16348 KB Output is correct
38 Correct 156 ms 16712 KB Output is correct
39 Correct 180 ms 16936 KB Output is correct
40 Correct 165 ms 16640 KB Output is correct
41 Correct 222 ms 21096 KB Output is correct