BZOJ1047: [HAOI2007]理想的正方形

Posted 2020-08-09

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蛤省省选果然水啊，我这种蒟蒻都能一遍A。

横向纵向维护两个单调队列，做两次求最大和最小的，总复杂度$O(NM)$

 

码农题，考察代码实现能力

 

  1 //BZOJ 1047
  2 //by Cydiater
  3 //2016.9.17
  4 #include <iostream>
  5 #include <cstdio>
  6 #include <cstdlib>
  7 #include <cstring>
  8 #include <cmath>
  9 #include <ctime>
 10 #include <map>
 11 #include <iomanip>
 12 #include <string>
 13 #include <algorithm>
 14 #include <queue>
 15 using namespace std;
 16 #define ll long long
 17 #define up(i,j,n)        for(int i=j;i<=n;i++)
 18 #define down(i,j,n)        for(int i=j;i>=n;i--)
 19 const int MAXN=1e3+5;
 20 const int oo=0x3f3f3f3f;
 21 inline int read(){
 22     char ch=getchar();int x=0,f=1;
 23     while(ch>‘9‘||ch<‘0‘){if(ch==‘-‘)f=-1;ch=getchar();}
 24     while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
 25     return x*f;
 26 }
 27 int N,M,K,a[MAXN][MAXN],head[MAXN],tail[MAXN],lable_max[MAXN][MAXN],lable_min[MAXN][MAXN],q[MAXN][MAXN],extro_q[MAXN],extro_head,extro_tail,ans=oo;
 28 namespace solution{
 29     inline void push(int co,int id){q[co][++tail[co]]=id;}
 30     void init(){
 31         N=read();M=read();K=read();
 32         up(i,1,N)up(j,1,M)a[i][j]=read();
 33     }
 34     void Queue_max(){
 35         memset(tail,0,sizeof(tail));
 36         up(i,1,N)head[i]=1;
 37         up(i,1,N)up(j,1,K){
 38             while(head[i]<=tail[i]&&a[i][j]>a[i][q[i][tail[i]]])tail[i]--;
 39             push(i,j);//load y
 40         }
 41         extro_head=1;extro_tail=0;
 42         up(i,1,K-1){
 43             while(extro_head<=extro_tail&&a[i][q[i][head[i]]]>a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 44             extro_q[++extro_tail]=i;//load x
 45         }
 46         up(i,K,N){
 47             while(i-extro_q[extro_head]+1>K&&extro_head<=extro_tail)extro_head++;
 48             while(extro_head<=extro_tail&&a[i][q[i][head[i]]]>a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 49             extro_q[++extro_tail]=i;//load x
 50             lable_max[i][K]=a[extro_q[extro_head]][q[extro_q[extro_head]][head[extro_q[extro_head]]]];
 51         }
 52         up(j,K+1,M){
 53             up(i,1,N){
 54                 while(j-q[i][head[i]]+1>K&&head[i]<=tail[i])head[i]++;
 55                 while(head[i]<=tail[i]&&a[i][j]>a[i][q[i][tail[i]]])tail[i]--;
 56                 push(i,j);//load y
 57             }
 58             extro_head=1;extro_tail=0;
 59             up(i,1,K-1){
 60                 while(extro_head<=extro_tail&&a[i][q[i][head[i]]]>a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 61                 extro_q[++extro_tail]=i;//load x
 62             }
 63             up(i,K,N){
 64                 while(i-extro_q[extro_head]+1>K&&extro_head<=extro_tail)extro_head++;
 65                 while(extro_head<=extro_tail&&a[i][q[i][head[i]]]>a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 66                 extro_q[++extro_tail]=i;//load x
 67                 lable_max[i][j]=a[extro_q[extro_head]][q[extro_q[extro_head]][head[extro_q[extro_head]]]];
 68             }
 69         }
 70     }
 71     void Queue_min(){
 72         memset(tail,0,sizeof(tail));
 73         up(i,1,N)head[i]=1;
 74         up(i,1,N)up(j,1,K){
 75             while(head[i]<=tail[i]&&a[i][j]<a[i][q[i][tail[i]]])tail[i]--;
 76             push(i,j);//load y
 77         }
 78         extro_head=1;extro_tail=0;
 79         up(i,1,K-1){
 80             while(extro_head<=extro_tail&&a[i][q[i][head[i]]]<a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 81             extro_q[++extro_tail]=i;//load x
 82         }
 83         up(i,K,N){
 84             while(i-extro_q[extro_head]+1>K&&extro_head<=extro_tail)extro_head++;
 85             while(extro_head<=extro_tail&&a[i][q[i][head[i]]]<a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 86             extro_q[++extro_tail]=i;//load x
 87             lable_min[i][K]=a[extro_q[extro_head]][q[extro_q[extro_head]][head[extro_q[extro_head]]]];
 88         }
 89         up(j,K+1,M){
 90             up(i,1,N){
 91                 while(j-q[i][head[i]]+1>K&&head[i]<=tail[i])head[i]++;
 92                 while(head[i]<=tail[i]&&a[i][j]<a[i][q[i][tail[i]]])tail[i]--;
 93                 push(i,j);//load y
 94             }
 95             extro_head=1;extro_tail=0;
 96             up(i,1,K-1){
 97                 while(extro_head<=extro_tail&&a[i][q[i][head[i]]]<a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
 98                 extro_q[++extro_tail]=i;//load x
 99             }
100             up(i,K,N){
101                 while(i-extro_q[extro_head]+1>K&&extro_head<=extro_tail)extro_head++;
102                 while(extro_head<=extro_tail&&a[i][q[i][head[i]]]<a[extro_q[extro_tail]][q[extro_q[extro_tail]][head[extro_q[extro_tail]]]])extro_tail--;
103                 extro_q[++extro_tail]=i;//load x
104                 lable_min[i][j]=a[extro_q[extro_head]][q[extro_q[extro_head]][head[extro_q[extro_head]]]];
105             }
106         }        
107     }
108     void slove(){
109         Queue_max();
110         Queue_min();
111     }
112     void output(){
113         /*up(i,1,N){
114             up(j,1,M)cout<<lable_max[i][j]<<‘ ‘;
115             cout<<endl;
116         }
117         puts("");
118         up(i,1,N){
119             up(j,1,M)cout<<lable_min[i][j]<<‘ ‘;
120             cout<<endl;
121         }
122         puts("");*/
123         up(i,K,N)up(j,K,M)ans=min(ans,lable_max[i][j]-lable_min[i][j]);
124         cout<<ans<<endl;
125     }
126 }
127 int main(){
128     //freopen("input.in","r",stdin);
129     using namespace solution;
130     init();
131     slove();
132     output();
133     return 0;
134 }

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妈的，下次再也不起这么长的变量名了，敲到手麻