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Submission #369172

# Submission time Handle Problem Language Result Execution time Memory
369172 2021-02-20T16:03:52 Z BartolM Beads and wires (APIO14_beads) C++17
100 / 100
 282 ms 22240 KB 
#include <bits/stdc++.h>

using namespace std;

#define X first
#define Y second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <int, pii> pip;
typedef pair <pii, int> ppi;
typedef pair <ll, ll> pll;

const int INF=0x3f3f3f3f;
const ll MAX=(ll)INF*INF;
const int N=2e5+5;

int n;
vector <pii> ls[N];
int dp[N][2];

int rek(int node, int fl, int par) {
    int &ret=dp[node][fl];
    if (ret!=-1) return ret;

    int sum0=0, ed;
    for (pii sus:ls[node]) {
        if (sus.X==par) {
            ed=sus.Y;
            continue;
        }
        sum0+=rek(sus.X, 0, node);
    }
    ret=sum0;
    for (pii sus:ls[node]) {
        if (sus.X==par) continue;
        if (!fl) ret=max(ret, ed+sus.Y+sum0-rek(sus.X, 0, node)+rek(sus.X, 1, node));
    }
    return ret;
}

void pokreni(int node, int par) {
    rek(node, 0, par);
    rek(node, 1, par);
    for (pii sus:ls[node]) if (sus.X!=par) pokreni(sus.X, node);
}

int dfs(int node, int par, int val0, int val1) {
    int sum0=val0, ed=0;
    for (pii sus:ls[node]) {
        if (sus.X==par) {
            ed=sus.Y;
            continue;
        }
        sum0+=dp[sus.X][0];
    }
    int ret=sum0;
    int maxi[2]={sum0+ed-val0+val1, 0};
    if (!par) maxi[0]=0;
    for (pii sus:ls[node]) {
        if (sus.X==par) continue;

        int x=sum0+sus.Y-dp[sus.X][0]+dp[sus.X][1];
        for (int i=0; i<2; ++i) if (x>maxi[i]) swap(x, maxi[i]);
    }

    int p0, p1=sum0;
    for (pii sus:ls[node]) {
        if (sus.X==par) continue;
        int curr=sum0+sus.Y-dp[sus.X][0]+dp[sus.X][1];

        if (maxi[0]==curr) p0=maxi[1]+sus.Y-dp[sus.X][0];
        else p0=maxi[0]+sus.Y-dp[sus.X][0];
        ret=max(ret, dfs(sus.X, node, max(p1-dp[sus.X][0], p0), p1-dp[sus.X][0]));
    }
    return ret;
}

void load() {
    scanf("%d", &n);
    for (int i=0; i<n-1; ++i) {
        int a, b, c;
        scanf("%d %d %d", &a, &b, &c);
        ls[a].pb(mp(b, c));
        ls[b].pb(mp(a, c));
    }
}

int main() {
    load();
    memset(dp, -1, sizeof dp);
    pokreni(1, 0);
    int p[2]={0, 0};
    printf("%d\n", dfs(1, 0, 0, 0));
    return 0;
}

Compilation message

beads.cpp: In function 'int main()':
beads.cpp:94:9: warning: unused variable 'p' [-Wunused-variable]
   94 |     int p[2]={0, 0};
      |         ^
beads.cpp: In function 'void load()':
beads.cpp:81:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   81 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
beads.cpp:84:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   84 |         scanf("%d %d %d", &a, &b, &c);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp: In function 'int rek(int, int, int)':
beads.cpp:38:33: warning: 'ed' may be used uninitialized in this function [-Wmaybe-uninitialized]
   38 |         if (!fl) ret=max(ret, ed+sus.Y+sum0-rek(sus.X, 0, node)+rek(sus.X, 1, node));
      |                                 ^

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 6636 KB Output is correct
2 Correct 4 ms 6636 KB Output is correct
3 Correct 4 ms 6636 KB Output is correct
4 Correct 4 ms 6636 KB Output is correct
5 Correct 5 ms 6636 KB Output is correct
6 Correct 4 ms 6636 KB Output is correct
7 Correct 5 ms 6636 KB Output is correct
8 Correct 4 ms 6636 KB Output is correct
9 Correct 4 ms 6636 KB Output is correct
10 Correct 6 ms 6636 KB Output is correct
11 Correct 5 ms 6636 KB Output is correct
12 Correct 4 ms 6636 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 6636 KB Output is correct
2 Correct 4 ms 6636 KB Output is correct
3 Correct 4 ms 6636 KB Output is correct
4 Correct 4 ms 6636 KB Output is correct
5 Correct 5 ms 6636 KB Output is correct
6 Correct 4 ms 6636 KB Output is correct
7 Correct 5 ms 6636 KB Output is correct
8 Correct 4 ms 6636 KB Output is correct
9 Correct 4 ms 6636 KB Output is correct
10 Correct 6 ms 6636 KB Output is correct
11 Correct 5 ms 6636 KB Output is correct
12 Correct 4 ms 6636 KB Output is correct
13 Correct 4 ms 6636 KB Output is correct
14 Correct 4 ms 6636 KB Output is correct
15 Correct 4 ms 6636 KB Output is correct
16 Correct 4 ms 6636 KB Output is correct
17 Correct 5 ms 6636 KB Output is correct
18 Correct 5 ms 6636 KB Output is correct
19 Correct 5 ms 6636 KB Output is correct
20 Correct 4 ms 6636 KB Output is correct
21 Correct 4 ms 6636 KB Output is correct
22 Correct 5 ms 6636 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 6636 KB Output is correct
2 Correct 4 ms 6636 KB Output is correct
3 Correct 4 ms 6636 KB Output is correct
4 Correct 4 ms 6636 KB Output is correct
5 Correct 5 ms 6636 KB Output is correct
6 Correct 4 ms 6636 KB Output is correct
7 Correct 5 ms 6636 KB Output is correct
8 Correct 4 ms 6636 KB Output is correct
9 Correct 4 ms 6636 KB Output is correct
10 Correct 6 ms 6636 KB Output is correct
11 Correct 5 ms 6636 KB Output is correct
12 Correct 4 ms 6636 KB Output is correct
13 Correct 4 ms 6636 KB Output is correct
14 Correct 4 ms 6636 KB Output is correct
15 Correct 4 ms 6636 KB Output is correct
16 Correct 4 ms 6636 KB Output is correct
17 Correct 5 ms 6636 KB Output is correct
18 Correct 5 ms 6636 KB Output is correct
19 Correct 5 ms 6636 KB Output is correct
20 Correct 4 ms 6636 KB Output is correct
21 Correct 4 ms 6636 KB Output is correct
22 Correct 5 ms 6636 KB Output is correct
23 Correct 7 ms 6764 KB Output is correct
24 Correct 7 ms 6764 KB Output is correct
25 Correct 7 ms 6764 KB Output is correct
26 Correct 10 ms 6892 KB Output is correct
27 Correct 11 ms 6892 KB Output is correct
28 Correct 10 ms 7020 KB Output is correct
29 Correct 9 ms 7020 KB Output is correct
30 Correct 9 ms 7020 KB Output is correct
31 Correct 10 ms 7404 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 6636 KB Output is correct
2 Correct 4 ms 6636 KB Output is correct
3 Correct 4 ms 6636 KB Output is correct
4 Correct 4 ms 6636 KB Output is correct
5 Correct 5 ms 6636 KB Output is correct
6 Correct 4 ms 6636 KB Output is correct
7 Correct 5 ms 6636 KB Output is correct
8 Correct 4 ms 6636 KB Output is correct
9 Correct 4 ms 6636 KB Output is correct
10 Correct 6 ms 6636 KB Output is correct
11 Correct 5 ms 6636 KB Output is correct
12 Correct 4 ms 6636 KB Output is correct
13 Correct 4 ms 6636 KB Output is correct
14 Correct 4 ms 6636 KB Output is correct
15 Correct 4 ms 6636 KB Output is correct
16 Correct 4 ms 6636 KB Output is correct
17 Correct 5 ms 6636 KB Output is correct
18 Correct 5 ms 6636 KB Output is correct
19 Correct 5 ms 6636 KB Output is correct
20 Correct 4 ms 6636 KB Output is correct
21 Correct 4 ms 6636 KB Output is correct
22 Correct 5 ms 6636 KB Output is correct
23 Correct 7 ms 6764 KB Output is correct
24 Correct 7 ms 6764 KB Output is correct
25 Correct 7 ms 6764 KB Output is correct
26 Correct 10 ms 6892 KB Output is correct
27 Correct 11 ms 6892 KB Output is correct
28 Correct 10 ms 7020 KB Output is correct
29 Correct 9 ms 7020 KB Output is correct
30 Correct 9 ms 7020 KB Output is correct
31 Correct 10 ms 7404 KB Output is correct
32 Correct 46 ms 9344 KB Output is correct
33 Correct 64 ms 9168 KB Output is correct
34 Correct 42 ms 9196 KB Output is correct
35 Correct 277 ms 17684 KB Output is correct
36 Correct 282 ms 17516 KB Output is correct
37 Correct 282 ms 17644 KB Output is correct
38 Correct 190 ms 18140 KB Output is correct
39 Correct 195 ms 17996 KB Output is correct
40 Correct 207 ms 17956 KB Output is correct
41 Correct 280 ms 22240 KB Output is correct