Submission #1099123

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099123		icebear	Race (IOI11_race)	C++14	Compilation error	0 ms	0 KiB

race

// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<ii, int> iii;

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i, n) for(int i=0; i<(n); ++i)
#define red(i, n) for(int i=(n)-1; i>=0; --i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define ar(x) array<int, (x)>
#define all(x) x.begin(), x.end()
#define task "icebearat"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll LLinf = 1e18 + 27092008;
const int N = 2e5 + 5;
int numNode, K;
vector<ii> G[N];
bool isCentroid[N];
int sz[N];

void DFS(int u, int par) {
	sz[u] = 1;
	for(ii e : G[u]) 
		if (e.fi != par && !isCentroid[e.fi]) {
			DFS(e.fi, u);
			sz[u] += sz[e.fi];
		}
}

int findCentroid(int u, int par, const int &subtreeSize) {
	for(ii e : G[u])
		if (e.fi != par && !isCentroid[e.fi] && sz[e.fi] > subtreeSize / 2)
			return findCentroid(e.fi, u, subtreeSize);
	return u;
}

int ans;
map<int, int> minEdge;

void dfs(int u, bool filling, int numWeight, int numEdge = 1, int par = -1) {
	if (numWeight > K) return;

	if (filling) {
		if (minEdge.find(numWeight) == minEdge.end()) 
			minEdge[numWeight] = numEdge;
		else 
			minEdge[numWeight] = min(minEdge[numWeight], numEdge);
	}
	else {
		if (minEdge.find(K - numWeight) != minEdge.end())
			ans = min(ans, minEdge[K - numWeight] + numEdge);
	}
	
	for(ii e : G[u])
		if (e.fi != par && !isCentroid[e.fi]) 
			dfs(e.fi, filling, numWeight + e.se, numEdge + 1, u);
}

void buildCentroid(int u) {
	DFS(u, -1);
	int centroid = findCentroid(u, -1, sz[u]);
	isCentroid[centroid] = true;
	
	minEdge.clear();
	minEdge[0] = 0;	
	
	for(ii e : G[centroid]) 
		if (!isCentroid[e.fi]) {
			dfs(e.fi, false, e.se);
			dfs(e.fi, true, e.se);
		}
		
	for(ii e : G[centroid])
		if (!isCentroid[e.fi])
			buildCentroid(e.fi);
}

void solve() {
	cin >> numNode >> K;
	FOR(i, 1, numNode - 1) {
		int u, v, w;
		cin >> u >> v >> w;
		u++, v++;
		G[u].pb(mp(v, w));
		G[v].pb(mp(u, w));
	}
	
	ans = inf;
	
	buildCentroid(1); 
	cout << (ans == inf ? -1 : ans);
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) solve();
    return 0;
}

Compilation message (stderr)

race.cpp: In function 'int main()':
race.cpp:107:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
race.cpp:108:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  108 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/ld: /tmp/cczDMHok.o: in function `main':
race.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccAAApsn.o:grader.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/ccAAApsn.o: in function `main':
grader.cpp:(.text.startup+0x28): undefined reference to `best_path(int, int, int (*) [2], int*)'
collect2: error: ld returned 1 exit status