Submission #681928

#	Time	Username	Problem	Language	Result	Execution time	Memory
681928		MilosMilutinovic	Tug of War (BOI15_tug)	C++14	23 / 100	381 ms	5476 KiB

tug

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <bitset>
#include <array>
using namespace std;

typedef long long ll;

const int N = 30333;
int n, k;
int l[2 * N];
int r[2 * N];
int s[2 * N];
vector<int> g[4 * N];
int ver;
int pos;
bool was[4 * N];
ll sum[2];

void addEdge(int v, int u) {
	g[v].push_back(u);
	g[u].push_back(v);
}

void dfs(int v) {
	if (v < 2 * n) {
		sum[ver & 1] += s[v];
		ver++;
	} else pos++;
	was[v] = true;
	for (int u : g[v])
		if (!was[u])
			dfs(u);
}

int main()
{
//	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);

	scanf("%d%d", &n, &k);
	assert(k >= 0);
	for (int i = 0; i < 2 * n; i++) {
		scanf("%d%d%d", &l[i], &r[i], &s[i]);
		--l[i];--r[i];
		addEdge(i, 2 * n + l[i]);
		addEdge(i, 3 * n + r[i]);
	}
	vector<int> diff;
	for (int i = 0; i < 2 * n; i++) if (!was[i]) {
		ver = 0;
		pos = 0;
		sum[0] = 0;
		sum[1] = 0;
		dfs(i);
		diff.push_back(sum[0] - sum[1]);
		if (ver > pos) {
			printf("NO\n");
			return 0;
		}
	}
	bitset<40 * N + 1> dp;
	dp[20 * N] = 1;
	for (int x : diff) {
		x = abs(x);
		dp = ((dp >> x) | (dp << x));
	}
	bool ok = false;
	for (int i = 0; i <= k; i++)
		if (dp[20 * N + i] || dp[20 * N - i])
			ok = true;
	if (ok)
		printf("YES\n");
	else
		printf("NO\n");

	return 0;
}

Compilation message (stderr)

tug.cpp: In function 'int main()':
tug.cpp:57:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |  scanf("%d%d", &n, &k);
      |  ~~~~~^~~~~~~~~~~~~~~~
tug.cpp:60:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |   scanf("%d%d%d", &l[i], &r[i], &s[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 18
• Subtask 2: 0 / 30
• Subtask 3: 23 / 23
• Subtask 4: 0 / 29