oj.uz

Submission #122428

# Submission time Handle Problem Language Result Execution time Memory
122428 2019-06-28T07:55:16 Z 이온조(#2989) Beads and wires (APIO14_beads) C++14
0 / 100
 8 ms 5120 KB 
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;

vector<pii> adj[200009];
int D[3][200009], V[200009];

int go(int x, int p, int pc) {
	for(auto& it: adj[x]) if(it.first != p) go(it.first, x, it.second);
	int s = 0, m1 = -1, m2 = -1;
	for(auto& it: adj[x]) if(it.first != p) s += max(D[0][it.first], D[1][it.first]);
	for(auto& it: adj[x]) if(it.first != p) {
		int n, c; tie(n, c) = it;
		V[n] = D[0][n] + c - max(D[0][n], D[1][n]);
		if(m1 == -1 || V[m1] <= V[n]) m2 = m1, m1 = n;
		else if(m2 == -1 || V[m2] <= V[n]) m2 = n;
	}
	D[0][x] = s;
	if(m1 != -1) D[1][x] = s + pc + V[m1];
	else D[1][x] = -1e9;

	D[2][x] = -1e9;
	if(m2 != -1) D[2][x] = s + V[m1] + V[m2];
	for(auto& it: adj[x]) if(it.first != p) {
		int n, c; tie(n, c) = it;
		if(n == m1) D[2][x] = max(D[2][x], s - max(D[0][n], D[1][n]) + D[2][n] + c + V[m2]);
		else D[2][x] = max(D[2][x], s - max(D[0][n], D[1][n]) + D[2][n] + c + V[m1]);
	}
	int mx = -1e9;
	for(auto& it: adj[x]) if(it.first != p) {
		int n, c; tie(n, c) = it;
		mx = max(mx, D[2][c] - max(D[0][c], D[1][c]));
	}
	D[2][x] = max(D[2][x], s + mx);

	// printf("x: %d, D0: %d, D1: %d, D2: %d, m1: %d, m2: %d, s: %d\n", x, D[0][x], D[1][x], D[2][x], m1, m2, s);
}

int main() {
	int N; scanf("%d",&N);
	for(int i=0; i<N-1; i++) {
		int u, v, w; scanf("%d%d%d",&u,&v,&w);
		adj[u].push_back({v, w});
		adj[v].push_back({u, w});
	}
	go(1, 1, -1e9);
	printf("%d", max(D[0][1], D[2][1]));
	return 0;
}

Compilation message

beads.cpp: In function 'int go(int, int, int)':
beads.cpp:37:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
beads.cpp: In function 'int main()':
beads.cpp:40:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  int N; scanf("%d",&N);
         ~~~~~^~~~~~~~~
beads.cpp:42:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v, w; scanf("%d%d%d",&u,&v,&w);
                ~~~~~^~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 6 ms 4992 KB Output is correct
3 Incorrect 8 ms 5120 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 6 ms 4992 KB Output is correct
3 Incorrect 8 ms 5120 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 6 ms 4992 KB Output is correct
3 Incorrect 8 ms 5120 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 6 ms 4992 KB Output is correct
3 Incorrect 8 ms 5120 KB Output isn't correct
4 Halted 0 ms 0 KB -