# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
25839 | gs14004 | Pipes (BOI13_pipes) | C++11 | 143 ms | 10288 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
typedef pair<int,int> pi;
typedef long long lint;
int n, m;
int deg[100005];
bool vis[100005];
int a[100005];
int ret[100005];
vector<pi> graph[100005];
queue<int> q;
int curval[100005], nxt[100005], cycsz;
int main(){
scanf("%d %d",&n,&m);
if(n < m){
puts("0");
return 0;
}
for(int i=1; i<=n; i++){
scanf("%d",&a[i]);
}
for(int i=0; i<m; i++){
int s, e;
scanf("%d %d",&s,&e);
graph[s].push_back(pi(i, e));
graph[e].push_back(pi(i, s));
deg[s]++, deg[e]++;
}
for(int i=1; i<=n; i++){
if(deg[i] == 1){
q.push(i);
}
}
while(!q.empty()){
int x = q.front();
q.pop();
deg[x] = 0;
vis[x] = 1;
for(int i=0; i<graph[x].size(); i++){
int pos = graph[x][i].second;
if(vis[pos]) continue;
deg[pos]--;
ret[graph[x][i].first] = 2 * a[x];
a[pos]-=a[x];
if(deg[pos] == 1){
q.push(pos);
}
}
}
int pos;
for(int i=1; i<=n; i++){
if(deg[i]) cycsz++, pos = i;
}
if(n == m && cycsz % 2 == 0){
puts("0");
return 0;
}
lint sum = 0;
for(int i=0; i<cycsz; i++){
curval[i] = pos;
sum += a[pos];
for(int j=0; j<graph[pos].size(); j++){
pi edg = graph[pos][j];
if(deg[edg.second]){
deg[edg.second] = 0;
nxt[i] = edg.first;
pos = edg.second;
break;
}
}
}
if(cycsz){
sum /= 2;
lint tsum = 0;
for(int i=0; i<cycsz/2; i++){
tsum += a[curval[(2+2*i) % cycsz]];
}
ret[nxt[0]] = 2 * (sum - tsum);
int pt = 0;
for(int i=2; i!=0; i = (i + 2) % cycsz){
tsum -= a[curval[i]];
tsum += a[curval[(i + cycsz / 2 * 2) % cycsz]];
ret[nxt[i]] = 2 * (sum - tsum);
}
}
for(int i=0; i<m; i++){
printf("%d\n",ret[i]);
}
}
Compilation message (stderr)
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