"CF" 121 Div.1 C. Fools and Roads

Test instructions is given a tree. Also, given the following K queries:

An arbitrary two-point u,v is given, and the edges of the path from U to V are counted.

After k queries, the sum of the counts of each side is output separately.

The idea utilizes LCA, on cnt[u]++, cnt[v]++, and on Cnt[lca (U, v)]-= 2.
Dfs then solves the count of each side.

1 /*191C*/2#include <iostream>3#include <string>4#include <map>5#include <queue>6#include <Set>7#include <stack>8#include <vector>9#include <deque>Ten#include <algorithm> One#include <cstdio> A#include <cmath> -#include <ctime> -#include <cstring> the#include <climits> -#include <cctype> -#include <cassert> -#include <functional> +#include <iterator> -#include <iomanip> + using namespacestd; A //#pragma COMMENT (linker, "/stack:102400000,1024000") at  - #defineSTI set<int> - #defineStpii Set<pair<int, int> > - #defineMpii map<int,int> - #defineVI vector<int> - #definePII pair<int,int> in #defineVpii vector<pair<int,int> > - #defineRep (I, A, n) for (int i=a;i<n;++i) to #definePer (i, a, n) for (int i=n-1;i>=a;--i) + #defineCLR Clear - #definePB Push_back the #defineMP Make_pair * #defineFIR First $ #defineSEC SecondPanax Notoginseng #defineAll (x) (x). Begin (), (x). End () - #defineSZ (x) ((int) (x). Size ()) the #defineLson L, Mid, rt<<1 + #defineRson mid+1, R, rt<<1|1 A  the Const intMAXN = 1e5+5; + Const intMaxd = -; - Vpii E[MAXN]; $ BOOLVISIT[MAXN]; $ intANS[MAXN]; - intCNT[MAXN]; - intDEEP[MAXN]; the intPre[maxn][maxd]; - Wuyi voidDfsintUintFA) { the     intSZ =SZ (E[u]), V; -      WuDeep[u] = Deep[fa] +1; -Rep (I,0, SZ) { Aboutv =E[u][i].fir; $         if(v = =FA) -             Continue; -pre[v][0] =u; -Rep (J,1, Maxd) APRE[V][J] = pre[pre[v][j-1]][j-1]; + Dfs (v, u); the     } - } $  the intLCA (intUintv) { the     if(Deep[u] >Deep[v]) the swap (U, v); the     if(Deep[u] <Deep[v]) { -         intTMP = Deep[v]-Deep[u]; inRep (I,0, Maxd) { the             if(TMP & (1<<i)) thev =Pre[v][i]; About         } the     } the      the     if(U! =v) { +Per (I,0, Maxd) { -             if(Pre[u][i]! =Pre[v][i]) { theU =Pre[u][i];Bayiv =Pre[v][i]; the             } the         } -         returnpre[u][0]; -}Else { the         returnu; the     } the } the  - intDFS2 (intUintEid) { the     intRET =0, Sz =SZ (E[u]); the     inte, V; the     94Visit[u] =true; theRep (I,0, SZ) { thev =E[u][i].fir; theE =e[u][i].sec;98         if(!Visit[v]) { AboutRET + =DFS2 (V, e); -         }101     }102RET + =Cnt[u];103Ans[eid] =ret;104      the     returnret;106 }107 108 intMain () {109Ios::sync_with_stdio (false); the #ifndef Online_judge111Freopen ("data.in","R", stdin); theFreopen ("Data.out","W", stdout);113     #endif the      the     intN; the     intu, v, FA;117     118scanf"%d", &n);119Rep (I,1, N) { -scanf"%d%d", &u, &v);121 E[U].PB (MP (V, i));122 E[V].PB (MP (U, i));123     }124      theDfs1,0);126     127     intK; -     129scanf"%d", &k); the      while(k--) {131scanf"%d%d", &u, &v); theFA =LCA (U, v);133++Cnt[u];134++Cnt[v];135CNT[FA]-=2;136     }137     138DFS2 (1,0);139Rep (I,1, N) $printf"%d", Ans[i]);141Putchar ('\ n');142     143 #ifndef Online_judge144printf"Time =%d.\n", (int) clock ());145     #endif146     147     return 0;148}

"CF" 121 Div.1 C. Fools and Roads