Summer Training Mania Brush Series--hdu 1698 Just a Hook (segment tree interval update)

Topic Connection:

http://acm.hdu.edu.cn/showproblem.php?pid=1698

Main topic:

There is a hook consisting of n sticks, the stick has three kinds of copper and silver gold, the value is three-in-one. In order to deal with each battle you need to adjust the stick that makes up a certain interval of the hook. Q. What is the total value of the hooks after Q-tuning?

Problem Solving Ideas:

Segment Tree Update. Each update to the node will be tle because of a data range problem. The interval update will save a lot of time, for each interval, if the stick inside the interval is the same type, a node variable is used to record the stick type, and if the stick is different type in the interval, the variable is recorded as-1.

1 //#include <bits/stdc++.h>2#include <cstdio>3#include <cstring>4#include <iostream>5#include <algorithm>6 using namespacestd;7 Const intManx =400000;8 structnode9 {Ten     intL, R, X; One     intMid () A     { -         return(L+R)/2; -     } the } Tree[manx]; - voidBuild (intRootintLintR) -{//achievements, sticks are copper -TREE[ROOT].L =l; +TREE[ROOT].R =R; -tree[root].x =1; +     if(L = =R) A         return ; atBuild (2*root+1, L, Tree[root]. Mid ()); -Build (2*root+2, Tree[root]. Mid () +1, R); - } - voidUpdate (intRootintLintRints) - { -     if(Tree[root].l==l && tree[root].r==R) in{//the current range is a stick of type S -tree[root].x =s; to         return ; +     } -     Else if(tree[root].x! =-1) the{//current interval Stick is not the same, need to transfer the state of the current interval to the left and right sub-tree and mark the current interval *tree[2*root+1].x = tree[2*root+2].x =tree[root].x; $tree[root].x =-1;Panax Notoginseng     } -     if(R <=Tree[root]. Mid ()) theUpdate (2*root+1, L, R, s); +     Else if(L >Tree[root]. Mid ()) AUpdate (2*root+2, L, R, s); the     Else +     { -Update (2*root+1, L, Tree[root]. Mid (), s); $Update (2*root+2, Tree[root]. Mid () +1, R, s); $     } - } - intSum (intRootintLints) the { -     if(tree[root].x! =-1)//The current interval stick type is no longer queried downwardWuyi         returntree[root].x * (S-l +1); the     Else -     { Wu         returnSum (2*root+1, L, Tree[root]. Mid ()) + Sum (2*root+2, Tree[root]. Mid () +1, s); -     } About } $ intMain () - { -     intT, L =0; -scanf ("%d", &t); A      while(T--) +     { the         intN, Q; -scanf ("%d%d", &n, &q); $Build (0,1, n); the          while(Q--) the         { the             intA, B, X; thescanf (" %d%d%d", &a, &b, &x); -Update (0, A, b, x); in         } the         intres = Sum (0,1, n); theprintf ("Case%d:the Total value of the hook is%d.\n", ++L, RES); About     } the     return 0; the}

　　

Summer Training Mania Brush Series--hdu 1698 Just a Hook (segment tree interval update)