func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 3e5;   int n, m, head[N], cnt, dep[N], fa[N], pid[N];   long long c[N], val[N];   bool vis[N], use[N];   struct edge {     int to, nxt, id;   } e[N << 1];   void finish() {     cout <<  YES n ;     for (int i = 1; i <= m; ++i) cout << val[i] <<   n ;     exit(0);   }   void dfs(int u) {     vis[u] = 1;     for (int i = head[u]; i; i = e[i].nxt)       if (!vis[e[i].to]) {         fa[e[i].to] = u;         dep[e[i].to] = dep[u] + 1;         pid[e[i].to] = e[i].id;         use[e[i].id] = 1;         dfs(e[i].to);       }     if (u != 1) {       val[pid[u]] = c[u];       c[fa[u]] -= c[u];       c[u] = 0;     }   }   void dfs2(int u) {     for (int i = head[u]; i; i = e[i].nxt)       if (!use[e[i].id] && (dep[e[i].to] - dep[u]) % 2 == 0) {         assert(dep[e[i].to] > dep[u]);         int fh = dep[u] % 2;         long long dlt = c[1] / 2;         if (fh == 1) dlt *= -1;         val[e[i].id] = dlt;         c[u] -= dlt, c[e[i].to] -= dlt;         for (int v = e[i].to; v != 1; v = fa[v]) {           val[pid[v]] += c[v];           c[fa[v]] -= c[v];           c[v] = 0;         }         assert(!c[1]);         finish();       }     for (int i = head[u]; i; i = e[i].nxt)       if (use[e[i].id] && dep[e[i].to] > dep[u]) dfs2(e[i].to);   }   int main() {     ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);     cin >> n >> m;     for (int i = 1; i <= n; ++i) cin >> c[i];     for (int i = 1; i <= m; ++i) {       int u, v;       cin >> u >> v;       e[++cnt] = (edge){v, head[u], i}, head[u] = cnt;       e[++cnt] = (edge){u, head[v], i}, head[v] = cnt;     }     dfs(1);     if (c[1] % 2 == 0) {       if (c[1])         dfs2(1);       else         finish();     }     cout <<  NO n ;     return 0;   }   