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Submission #369161

# Submission time Handle Problem Language Result Execution time Memory
369161 2021-02-20T15:40:35 Z BartolM Beads and wires (APIO14_beads) C++17
0 / 100
 1 ms 620 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=1e4+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;
//    printf("node: %d, val0: %d, val1: %d\n", node, val0, val1);
    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;
//    printf("node: %d, sum0: %d, maxi0: %d, maxi1: %d\n", node, sum0, maxi[0], maxi[1]);
    for (pii sus:ls[node]) {
        if (sus.X==par) continue;

        int x=sum0+sus.Y-dp[sus.X][0]+dp[sus.X][1];
//        printf("sus: %d, x == %d\n", sus.X, x);
        for (int i=0; i<2; ++i) if (x>maxi[i]) swap(x, maxi[i]);
    }
//    printf("maxi0: %d, maxi1: %d\n", maxi[0], maxi[1]);

    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];
//        printf("dijete: %d, p0 == %d, p1 == %d\n", sus.X, p0, p1-dp[sus.X][0]);
        ret=max(ret, dfs(sus.X, node, p0, p1-dp[sus.X][0]));
    }
//    printf("node: %d, sum0: %d, ret: %d\n", node, sum0, ret);
    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:100:9: warning: unused variable 'p' [-Wunused-variable]
  100 |     int p[2]={0, 0};
      |         ^
beads.cpp: In function 'void load()':
beads.cpp:87:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   87 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
beads.cpp:90:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   90 |         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
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 620 KB Output is correct
4 Correct 1 ms 620 KB Output is correct
5 Correct 1 ms 620 KB Output is correct
6 Correct 1 ms 620 KB Output is correct
7 Incorrect 1 ms 620 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 620 KB Output is correct
4 Correct 1 ms 620 KB Output is correct
5 Correct 1 ms 620 KB Output is correct
6 Correct 1 ms 620 KB Output is correct
7 Incorrect 1 ms 620 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 620 KB Output is correct
4 Correct 1 ms 620 KB Output is correct
5 Correct 1 ms 620 KB Output is correct
6 Correct 1 ms 620 KB Output is correct
7 Incorrect 1 ms 620 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 620 KB Output is correct
4 Correct 1 ms 620 KB Output is correct
5 Correct 1 ms 620 KB Output is correct
6 Correct 1 ms 620 KB Output is correct
7 Incorrect 1 ms 620 KB Output isn't correct
8 Halted 0 ms 0 KB -