#include <bits/stdc++.h> using namespace std; const int N = 200 + 5; int a[N]; vector <int> vec[N]; vector <int> fac[N]; vector <pair<double, double> > Node[N]; vector <pair<double, double> > tmp; bool vis[N]; double fini[N]; int n, m, B, E; void dfs(int v) {   tmp.clear();   if(v == B) {     vis[v] = 1; fini[v] = 1.0 * a[v] / (1.0 * E);     double flo = 0.0;     if(vec[v].size()) flo = 1.0 * E / (1.0 * vec[v].size());     tmp.push_back(make_pair(fini[v], flo));     Node[v] = tmp;     return ;   }   for(auto u: fac[v]) {     //cout << v << " " << u << endl;     if(!vis[u]) dfs(u);     for(auto x: Node[u]) {       tmp.push_back(x);       //cout << v << " " << u << " " << x.first << " " << x.second << endl;     }   }   vis[v] = 1;   if(tmp.size() == 0) {     fini[v] = -1.0; return ;   }   sort(tmp.begin(), tmp.end());   int tmpl = tmp.size();   double pre = 0.0;   double sum = 0.0;   int flg = -1;   for(int i = 0; i < tmpl-1; ++ i) {     pre += tmp[i].second;     double inv = tmp[i+1].first - tmp[i].first;     if(sum + inv*pre > 1.0 * a[v]) {       fini[v] = tmp[i].first + 1.0 * (1.0 * a[v] - sum) / pre;       flg = i; break;     }     sum += inv*pre;   }   if(flg == -1) {     double ptim = tmp[tmpl - 1].first;     //if(tmpl >= 2) ptim = tmp[tmpl - 2].first;     fini[v] = ptim + 1.0 * (1.0 * a[v] - sum) / (pre + tmp[tmpl - 1].second);     double fi = fini[v];     double se = pre + tmp[tmpl - 1].second;     tmp.resize(1);     tmp[0] = make_pair(fi, se / (1.0 * vec[v].size()));     Node[v] = tmp;     return ;   }   int nl = 0;   for(int i = flg; i < tmpl; ++ i) {     tmp[nl] = tmp[i];     tmp[nl].second = tmp[i].second / (1.0 * vec[v].size());     nl ++;   }   tmp[0].first = fini[v];   tmp[0].second = pre / (1.0 * vec[v].size());   tmp.resize(nl);   Node[v] = tmp;   return ; } int main() {   int T;   scanf("%d", &T);   while(T --) {     scanf("%d%d%d%d", &n, &m, &B, &E);     for(int i = 1; i <= n; ++ i) {       scanf("%d", a + i);       vec[i].clear();       fac[i].clear();       Node[i].clear();     }     for(int i = 1; i <= m; ++ i) {       int u, v;       scanf("%d%d", &u, &v);       vec[u].push_back(v);       fac[v].push_back(u);     }     memset(vis, 0, sizeof(vis));     for(int i = 1; i <= n; ++ i) {       if(!vis[i]) dfs(i);     }     for(int i = 1; i <= n; ++ i) {       printf("%.8f", fini[i]);       if(i != n) printf(" ");     }     printf("\n");   }   return 0; } 第三题，场上少写了个 nl++ 没过，还没改回来就时间到了 这是改完后的，不知道能不能过，希望哪位大佬能帮我看看