BZOJ1369 [Baltic2003]gem

is a simple tree DP ~ But the question is, how many colors do you want?

I began to write 25 in the color of the hand, and found that very slow ah ... So I did a dead change to three kinds of handed up to unexpectedly past ... After the ... (To know 2 colors must be wrong ah ...) ）

1 /**************************************************************2 problem:13693 User:rausen4 language:c++5 result:accepted6 Time:12 Ms7 memory:1820 KB8 ****************************************************************/9  Ten#include <cstdio> One#include <algorithm> A   - using namespacestd; - Const intN = 1e4 +5; the Const intINF =1e9; - Const intC =3; -   - structEdge { +     intnext, to; - Edge () {} +Edgeint_n,int_t): Next (_n), to (_t) {} A} e[n <<1]; at   - intN, ans; - intfirst[n], tot; - intf[n][ +]; -   -InlineintRead () { in     intx =0; -     CharCH =GetChar (); to      while(Ch <'0'||'9'<ch) +CH =GetChar (); -      while('0'<= CH && Ch <='9') { thex = x *Ten+ CH-'0'; *CH =GetChar (); $     }Panax Notoginseng     returnx; - } the   +   AInlinevoidAdd_edges (intXinty) { theE[++tot] = Edge (first[x], y), first[x] =tot; +E[++tot] = Edge (First[y], x), first[y] =tot; - } $   $ #defineY e[x].to - voidWorkintPintFA) { -     intx, I, J, MN; the      for(i =1; I <= C; ++i) F[p][i] =i; -      for(x = first[p]; x; x =e[x].next)Wuyi         if(Y! =fa) Work (Y, p); the      for(i =1; I <= C; ++i) { -          for(x = first[p]; x; x =e[x].next) Wu             if(Y! =FA) { -                  for(j =1, MN = inf; J <= C; ++j) About                     if(I! = j) mn =min (mn, f[y][j]); $F[p][i] + =mn; -             } -     } - } A #undefY +   the intMain () { -     inti; $n =read (); the      for(i =1; I < n; ++i) the add_edges (read (), read ()); theWork1,0); the      for(i =1, ans = inf; I <= C; ++i) -ans = min (ans, f[1][i]); inprintf"%d\n", ans); the     return 0; the}

View Code

BZOJ1369 [Baltic2003]gem