[CSUOJ1804] A direction-free graph (tree dp)

Title Link: http://acm.csu.edu.cn/OnlineJudge/problem.php?id=1804

Test instructions: The Chinese side, the formula is also very clear.

1e5 This is a very large number, because it is a DAG, it can be thought that the whole picture is a forest, the focus should be placed on each tree each point of the contribution of the whole problem.

Remember that each beginning U,v is the successor of U. V has multiple, credited Vi,u to VI contribution is COUNT (U,VI) *a (u) *b (vi), presents a (U), remaining count (U,vi) *b (vi), COUNT (U,VI) can be post-traversal to get, the entire result exists in DP (U), post-update the answer when the DP (u) *a (u). You can then update the B (vi) section, which is incremented to DP (U) each time, because the next visit (The father of U) must include the results of DP (U).

1 /*2 ━━━━━┒ギリギリ♂eye! 3 ┓┏┓┏┓┃キリキリ♂mind! 4 ┛┗┛┗┛┃\0/5 ┓┏┓┏┓┃/6 ┛┗┛┗┛┃ノ)7 ┓┏┓┏┓┃8 ┛┗┛┗┛┃9 ┓┏┓┏┓┃Ten ┛┗┛┗┛┃ One ┓┏┓┏┓┃ A ┛┗┛┗┛┃ - ┓┏┓┏┓┃ - ┃┃┃┃┃┃ the ┻┻┻┻┻┻ - */ -#include <algorithm> -#include <iostream> +#include <iomanip> -#include <cstring> +#include <climits> A#include <complex> at#include <fstream> -#include <cassert> -#include <cstdio> -#include <bitset> -#include <vector> -#include <deque> in#include <queue> -#include <stack> to#include <ctime> +#include <Set> -#include <map> the#include <cmath> * using namespacestd; $ #defineFr FirstPanax Notoginseng #defineSC Second - #defineCL Clear the #defineBUG puts ("Here!!!") + #defineW (a) while (a--) A #definePB (a) push_back (a) the #defineRint (a) scanf ("%d", &a) + #defineRll (a) scanf ("%i64d", &a) - #defineRs (a) scanf ("%s", a) $ #defineCIN (a) CIN >> a $ #defineFRead () freopen ("in", "R", stdin) - #defineFWrite () freopen ("Out", "w", stdout) - #defineRep (i, Len) for (int i = 0; i < (len); i++) the #defineFor (I, A, Len) for (int i = (a); I < (len); i++) - #defineCls (a) memset ((a), 0, sizeof (a))Wuyi #defineCLR (A, X) memset ((a), (x), sizeof (a)) the #defineFull (a) memset ((a), 0x7f7f7f, sizeof (a)) - #defineLRT RT << 1 Wu #defineRRT RT << 1 | 1 - #definePi 3.14159265359 About #defineRT return $ #defineLowbit (x) x & (-X) - #defineONECNT (x) __builtin_popcount (x) -typedefLong LongLL; -typedefLong DoubleLD; Atypedef unsignedLong LongULL; +typedef pair<int,int>PII; thetypedef pair<string,int>psi; -typedef PAIR&LT;LL, Ll>PLL; $typedef map<string,int>MSI; thetypedef vector<int>VI; thetypedef vector<ll>VL; thetypedef vector<vl>VVL; thetypedef vector<BOOL>vb; -  in Const intMAXN =100100; the ConstLL mod = 1e9+7; the intN, M; About intA[MAXN], B[MAXN]; the VI G[MAXN]; the BOOLVIS[MAXN]; the LL DP[MAXN]; + LL ret; -  the voidDfsintu) {Bayi Rep (i, g[u].size ()) { the         intv =G[u][i]; the         if(!Vis[v]) { -VIS[V] =1; - Dfs (v); the         } theDp[u] = (Dp[u] + dp[v])%MoD; the     } theRET = (ret + (dp[u] * a[u]% MoD))%MoD; -Dp[u] = (Dp[u] + b[u])%MoD; the } the  the intMain () {94     //FRead (); the     intu, v; the      while(~rint (n) &&~Rint (M)) { theRET =0; Cls (VIS); Cls (DP);98for (I,1, n+1) { About Rint (A[i]), Rint (B[i]); - g[i].clear ();101         }102 Rep (i, m) {103 Rint (U); Rint (v);104 G[U].PB (v); the         }106for (I,1, n+1) {107             if(!Vis[i]) DFS (i);108         }109for (I,1, n+1) cout << Dp[i] <<" "; thecout <<Endl;111cout << ret <<Endl; the     }113Rt0; the}

[CSUOJ1804] A direction-free graph (tree dp)