习题6-7　Petri网模拟（Petri Net Simulation, ACM/ICPC World Finals 1998, UVa804）

#include <iostream>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <sstream>
#include <utility>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <cctype>
#define CLEAR(a, b) memset(a, b, sizeof(a))
#define IN() freopen("in.txt", "r", stdin)
#define OUT() freopen("out.txt", "w", stdout)
#define LL long long
#define maxn 105
#define maxm 200005
#define mod 1000000007
#define INF 1000000007
#define eps 1e-5
#define PI 3.1415926535898
#define N 26
using namespace std;
//-------------------------CHC------------------------------//
int NP, NT;
int p[maxn];
struct T {
map<int, int> pre, next;
}t[maxn];

int main() {
int kase = 1;
while (scanf("%d", &NP) && NP) {
for (int i = 1; i <= NP; ++i) scanf("%d", &p[i]);
scanf("%d", &NT);
for (int i = 1; i <= NT; ++i) t[i].next.clear(), t[i].pre.clear();
int x;
for (int i = 1; i <= NT; ++i) {
while (scanf("%d", &x) && x) {
if (x < 0) t[i].pre[-x]++;
else t[i].next[x]++;
}
}
int trans;
scanf("%d", &trans);
int cnt = 0;
bool ok = true;
while (ok) {
ok = false;
for (int i = 1; i <= NT; ++i) {
bool can = true;
for (auto j : t[i].pre)
if (p[j.first] < j.second) can = false;
if (!can) continue;
for (auto j : t[i].pre)
p[j.first] -= j.second;
for (auto j : t[i].next)
p[j.first] += j.second;
cnt++, ok = true;
if (cnt >= trans) { ok = false; break; }
}
}
if (cnt >= trans)
printf("Case %d: still live after %d transitions\n", kase++, trans);
else
printf("Case %d: dead after %d transitions\n", kase++, cnt);
printf("Places with tokens:");
for (int i = 1; i <= NP; ++i)
if (p[i]) printf(" %d (%d)", i, p[i]);
puts("\n");
}
return 0;
}