Submission #111614

#	Time	Username	Problem	Language	Result	Execution time	Memory
111614		wilwxk	Pipes (BOI13_pipes)	C++11	65 / 100	445 ms	27436 KiB

pipes

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

const int MAXN=1e5+5;
vector<int> g[MAXN], lista[MAXN];
int v[MAXN], tenho[MAXN], resp[MAXN];
int n, m;

void dfs(int cur, int p) {
	tenho[cur]=0;
	for(int i=0; i<g[cur].size(); i++) {
		int viz=g[cur][i]; int ind=lista[cur][i];
		if(viz==p) continue;
		dfs(viz, cur);
		resp[ind]=v[viz]-tenho[viz];
		tenho[cur]+=resp[ind];
	}
}

int main() {
	scanf("%d %d", &n, &m);
	for(int i=1; i<=n; i++) scanf("%d", &v[i]);
	for(int i=1; i<=m; i++) {
		int a, b; scanf("%d %d", &a, &b);
		g[a].push_back(b); g[b].push_back(a);
		lista[a].push_back(i); lista[b].push_back(i);
	}

	if(m>n) {
		printf("0\n");
	}

	else if(m==n-1) {
		dfs(1, 1);
		if(tenho[1]!=v[1]) {
			printf("0\n");
		}
		else {
			for(int i=1; i<=m; i++) {
				printf("%d\n", resp[i]*2);
			}
		}
	}


}

Compilation message (stderr)

pipes.cpp: In function 'void dfs(int, int)':
pipes.cpp:11:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<g[cur].size(); i++) {
               ~^~~~~~~~~~~~~~
pipes.cpp: In function 'int main()':
pipes.cpp:21:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:22:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1; i<=n; i++) scanf("%d", &v[i]);
                          ~~~~~^~~~~~~~~~~~~
pipes.cpp:24:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int a, b; scanf("%d %d", &a, &b);
             ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 35 / 70