Codeforces 527C Glass Carving

题意：给你一个二维平面，m个询问横着和竖着划一条线，问你最大矩形面积是多少。

解题思路：

1）不知道为什么感觉不能用优先队列找最大值以后就脑抽的想到了线段树找最大值，真是悲剧的开始。

线段树 + map 迭代器

解题代码：

  1 // File Name: c.cpp
  2 // Author: darkdream
  3 // Created Time: 2015年03月18日 星期三 01时04分52秒
  4 
  5 #include<vector>
  6 #include<list>
  7 #include<map>
  8 #include<set>
  9 #include<deque>
 10 #include<stack>
 11 #include<bitset>
 12 #include<algorithm>
 13 #include<functional>
 14 #include<numeric>
 15 #include<utility>
 16 #include<sstream>
 17 #include<iostream>
 18 #include<iomanip>
 19 #include<cstdio>
 20 #include<cmath>
 21 #include<cstdlib>
 22 #include<cstring>
 23 #include<ctime>
 24 #define LL long long
 25 #define maxn 200005
 26 using namespace std;
 27 int w, h , n;
 28 char str[10];
 29 int v; 
 30 struct node{
 31   int l , r , m ,v,lazy;
 32 };
 33 map<int ,int> wmp;
 34 map<int ,int> hmp;
 35 class sg{
 36     public:
 37     struct node tree[maxn*4];
 38     int L(int x)
 39     {
 40        return 2 * x; 
 41     }
 42     int R(int x)
 43     {
 44        return 2* x + 1; 
 45     }
 46     void build(int c, int l , int r ,int v)
 47     {
 48           tree[c].l = l ; 
 49           tree[c].r = r; 
 50           tree[c].m = (l + r)/2;
 51           tree[c].lazy = 0 ; 
 52           if(l == r)
 53           {
 54               tree[c].v = v; 
 55               return;
 56           }
 57           build(L(c),l,tree[c].m,v);
 58           build(R(c),tree[c].m+1,tree[c].r,v);
 59           push_up(c);
 60     }
 61     void push_up(int c)
 62     {
 63          tree[c].v = max(tree[L(c)].v,tree[R(c)].v);
 64     }
 65     void push_down(int c)
 66     {
 67          if(tree[c].lazy != 0 )
 68          {
 69           tree[L(c)].v = tree[c].lazy; 
 70           tree[R(c)].v = tree[c].lazy;
 71           tree[L(c)].lazy = tree[c].lazy;
 72           tree[R(c)].lazy = tree[c].lazy;
 73           tree[c].lazy = 0 ;
 74          }
 75     }
 76     void update(int c, int l , int r,int v)
 77     {
 78       if(l <= tree[c].l && r >= tree[c].r)
 79       {
 80            //printf("%d**%d\n",tree[c].v,v);
 81            tree[c].lazy = v;
 82            tree[c].v = v; 
 83            return; 
 84       }
 85       push_down(c);
 86       if(l <= tree[c].m )
 87           update(L(c),l,r,v);
 88       if(r > tree[c].m)
 89           update(R(c),l,r,v);
 90       push_up(c);
 91     }
 92 
 93 }t1,t2; 
 94 int main(){
 95     scanf("%d %d %d",&w,&h,&n);
 96       t1.build(1,1,w,w);
 97       t1.tree[1].lazy = w; 
 98       t2.build(1,1,h,h); 
 99       t2.tree[1].lazy = h;
100       wmp[0] = 1; 
101       wmp[w] = 1; 
102       hmp[0] = 1; 
103       hmp[h] = 1;
104       map<int ,int >::iterator l,m,r;
105       int tmpv;  
106     for(int i = 1;i <= n;i ++)
107     {
108       scanf("%s %d",str,&tmpv);
109       if(str[0] == 'H')
110       {
111           if(hmp.find(tmpv) == hmp.end())
112           {
113               hmp[tmpv] = 1;
114               l = hmp.find(tmpv);
115               l --;
116               m = hmp.find(tmpv);
117               r = hmp.find(tmpv);
118               r ++ ; 
119               t2.update(1,l->first,m->first,m->first- l->first);
120               t2.update(1,m->first+1,r->first,r->first - m->first);
121         //      printf("%d %d\n",m->first - l->first+1,r->first - m->first);
122           }
123       }else{
124           if(wmp.find(tmpv)== wmp.end() )
125           {
126               wmp[tmpv] = 1;
127               l = wmp.find(tmpv);
128               l --;
129               m = wmp.find(tmpv);
130               r = wmp.find(tmpv);
131               r ++ ;
132         //      printf("%d %d\n",m->first ,l->first);
133               //if(l->first == 1 )
134               t1.update(1,l->first,m->first,m->first- l->first );
135               t1.update(1,m->first+1,r->first,r->first - m->first);
136         //      printf("%d %d %d\n",t1.tree[1].v,m->first - l->first+1,r->first - m->first);
137           }
138       }
139       //printf("%d %d\n",t1.tree[1].v,t2.tree[1].v);
140       printf("%I64d\n",1ll*t1.tree[1].v*t2.tree[1].v);
141     }
142 return 0;
143 }

View Code

2）set + multiset ，时间效率好像低一点点，但是真的好写.

解题代码：

 1 // File Name: c.1.cpp
 2 // Author: darkdream
 3 // Created Time: 2015年03月18日 星期三 10时08分02秒
 4 
 5 #include<vector>
 6 #include<list>
 7 #include<map>
 8 #include<set>
 9 #include<deque>
10 #include<stack>
11 #include<bitset>
12 #include<algorithm>
13 #include<functional>
14 #include<numeric>
15 #include<utility>
16 #include<sstream>
17 #include<iostream>
18 #include<iomanip>
19 #include<cstdio>
20 #include<cmath>
21 #include<cstdlib>
22 #include<cstring>
23 #include<ctime>
24 #define LL long long
25 
26 using namespace std;
27 int w,h , n; 
28 set<int>  wss,hs;
29 multiset<int> mwss,mhs;
30 char str[10];
31 int main(){
32     scanf("%d %d %d",&w,&h,&n);
33     wss.insert(0);
34     wss.insert(w);
35     hs.insert(h);
36     hs.insert(0);
37     mhs.insert(h);
38     mwss.insert(w);
39     set<int>::iterator l , r, m ; 
40     multiset<int>::iterator  tmp ; 
41     for(int i = 1;i <= n;i ++)
42     {
43        int tmpv; 
44        scanf("%s %d",str,&tmpv);
45        if(str[0]== 'H'){
46          if(hs.find(tmpv) == hs.end())
47          {
48              hs.insert(tmpv);
49              l = hs.find(tmpv);
50              l -- ; 
51              r = hs.find(tmpv);
52              r ++;
53              int t = *r - *l;
54         //     printf("%d\n",t);
55              tmp = mhs.find(t);
56              int k = * tmp ; 
57              mhs.erase(tmp);
58              mhs.insert(*r-tmpv);
59              mhs.insert(tmpv-*l);
60              
61          }
62        }else{
63          if(wss.find(tmpv) == wss.end())
64          {
65              wss.insert(tmpv);
66              l = wss.find(tmpv);
67              l -- ; 
68              r = wss.find(tmpv);
69              r ++;
70              int t = *r - *l;
71         //     printf("%d\n",t);
72              tmp = mwss.find(t);
73              int k = * tmp ; 
74              mwss.erase(tmp);
75              mwss.insert(*r-tmpv);
76              mwss.insert(tmpv-*l);
77          }
78        
79        }
80        tmp = mhs.end();
81        tmp -- ; 
82        LL sum = *tmp;
83        //printf("%d ",*tmp);
84        tmp = mwss.end();
85        tmp -- ;
86        sum *= (*tmp);
87        //printf(" %d\n",*tmp);
88        printf("%I64d\n",sum);
89     }
90 return 0;
91 }

View Code

posted on 2015-03-18 11:11 dark_dream 阅读(244) 评论(0) 编辑收藏举报