hdu 1540 Tunnel Warfare 线段树 单点更新，查询区间长度，区间合并

题目链接:

http://acm.hdu.edu.cn/showproblem.php?pid=1540

题意:

给你一个区间，有三个操作，使的一个村庄毁灭，使的上一个毁灭的村庄复活，查询这个村庄所在最长区间

题解:

区间合并的线段树，单点修改，记录从左边的最大值，右边的最大值，区间的最大值
然后每次更新

代码:

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 #define MS(a) memset(a,0,sizeof(a))
 5 #define MP make_pair
 6 #define PB push_back
 7 const int INF = 0x3f3f3f3f;
 8 const ll INFLL = 0x3f3f3f3f3f3f3f3fLL;
 9 inline ll read(){
10     ll x=0,f=1;char ch=getchar();
11     while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
12     while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
13     return x*f;
14 }
15 //////////////////////////////////////////////////////////////////////////
16 const int maxn = 1e5+10;
17 
18 struct node{
19     int l,r,lm,rm,mm,len;
20 }tree[maxn<<2];
21 
22 void pushup(int rt){
23     tree[rt].lm = tree[rt<<1].lm;
24     tree[rt].rm = tree[rt<<1|1].rm;
25     tree[rt].mm = max(max(tree[rt<<1].mm,tree[rt<<1|1].mm),tree[rt<<1].rm+tree[rt<<1|1].lm);
26     if(tree[rt<<1].lm == tree[rt<<1].len) tree[rt].lm = tree[rt<<1].lm + tree[rt<<1|1].lm;
27     if(tree[rt<<1|1].rm == tree[rt<<1|1].len) tree[rt].rm = tree[rt<<1].rm+tree[rt<<1|1].rm;
28 }
29 
30 void build(int rt,int l,int r){
31     tree[rt].l = l, tree[rt].r = r;
32     tree[rt].lm = tree[rt].rm = tree[rt].mm = tree[rt].len = r-l+1;
33     if(l != r){
34         int mid = (l+r)/2;
35         build(rt<<1,l,mid);
36         build(rt<<1|1,mid+1,r);
37         pushup(rt);
38     }
39 }
40 
41 void update(int rt,int p,int x){
42     int L = tree[rt].l, R = tree[rt].r;
43     if(L == R) { 
44         tree[rt].lm=tree[rt].rm=tree[rt].mm = x;
45         return ;
46     }
47 
48     int mid = (L+R)/2;
49     if(p <= mid) update(rt<<1,p,x);
50     else update(rt<<1|1,p,x);
51     pushup(rt);
52 }
53 
54 ll query(int rt,int p){
55     int L = tree[rt].l, R = tree[rt].r;
56     if(L==R || tree[rt].mm==0 || tree[rt].mm==tree[rt].len)
57         return tree[rt].mm;
58     int mid = (L+R)/2;
59     if(p<=mid){
60         if(p >= tree[rt<<1].r - tree[rt<<1].rm + 1){
61             return query(rt<<1,p) + query(rt<<1|1,mid+1);
62         }else{
63             return query(rt<<1,p);
64         }
65     }else{
66         if(p <= tree[rt<<1|1].l+tree[rt<<1|1].lm-1){
67             return query(rt<<1|1,p) + query(rt<<1,mid);
68         }else{
69             return query(rt<<1|1,p);
70         }
71     }
72 }
73 
74 int main(){
75     int n,m;
76     while(scanf("%d%d",&n,&m)!=EOF){
77         stack<int> k;
78         build(1,1,n);
79         for(int i=0; i<m; i++){
80             char op; scanf(" %c",&op);
81             int t;
82             if(op == 'D'){
83                 scanf("%d",&t);
84                 update(1,t,0);
85                 k.push(t);
86             }else if(op == 'Q'){
87                 scanf("%d",&t); 
88                 printf("%I64d\n",query(1,t));
89             }else{
90                 update(1,k.top(),1);
91                 k.pop();
92             }
93         }
94     }
95 
96     return 0;
97 }

 

posted @ 2017-03-02 18:09  _yxg123  阅读(114)  评论(0)  编辑  收藏  举报