【POJ】2019 Cornfields 
  1 #include<cstdio>
  2 #define MAXN 300
  3 struct node
  4 {
  5     int big[MAXN<<2],small[MAXN<<2];
  6 };
  7 node tree[MAXN<<2];
  8 int n,b;
  9 inline int MAX(int x,int y)
 10 {
 11     return x>y?x:y;
 12 }
 13 inline int MIN(int x,int y)
 14 {
 15     return x>y?y:x;
 16 }
 17 void SubBuild(int t,int L,int R,int rt)
 18 {
 19     tree[t].big[rt]=0;
 20     tree[t].small[rt]=MAXN;
 21     if(L!=R)
 22     {
 23         int mid=(L+R)>>1;
 24         SubBuild(t,L,mid,rt<<1);
 25         SubBuild(t,mid+1,R,rt<<1|1);
 26     }
 27 }
 28 void Build(int L,int R,int rt)
 29 {
 30     SubBuild(rt,1,n,1);
 31     if(L!=R)
 32     {
 33         int mid=(L+R)>>1;
 34         Build(L,mid,rt<<1);
 35         Build(mid+1,R,rt<<1|1);
 36     }
 37 }
 38 void SubUpdate(int t,int x,int val,int L,int R,int rt)
 39 {
 40     if(L==R)
 41     {
 42         tree[t].big[rt]=MAX(tree[t].big[rt],val);
 43         tree[t].small[rt]=MIN(tree[t].small[rt],val);
 44     }
 45     else
 46     {
 47         int mid=(L+R)>>1;
 48         if(x<=mid)
 49             SubUpdate(t,x,val,L,mid,rt<<1);
 50         else
 51             SubUpdate(t,x,val,mid+1,R,rt<<1|1);
 52         tree[t].big[rt]=MAX(tree[t].big[rt<<1],tree[t].big[rt<<1|1]);
 53         tree[t].small[rt]=MIN(tree[t].small[rt<<1],tree[t].small[rt<<1|1]);
 54     }
 55 }
 56 void Update(int x,int y,int val,int L,int R,int rt)
 57 {
 58     SubUpdate(rt,y,val,1,n,1);
 59     if(L!=R)
 60     {
 61         int mid=(L+R)>>1;
 62         if(x<=mid)
 63             Update(x,y,val,L,mid,rt<<1);
 64         else
 65             Update(x,y,val,mid+1,R,rt<<1|1);
 66     }
 67 }
 68 int SubQueryB(int t,int x,int y,int L,int R,int rt)
 69 {
 70     if(x<=L&&R<=y)
 71         return tree[t].big[rt];
 72     int mid=(L+R)>>1,ans=0;
 73     if(x<=mid)
 74         ans=MAX(ans,SubQueryB(t,x,y,L,mid,rt<<1));
 75     if(y>mid)
 76         ans=MAX(ans,SubQueryB(t,x,y,mid+1,R,rt<<1|1));
 77     return ans;
 78 }
 79 int QueryB(int x1,int x2,int y1,int y2,int L,int R,int rt)
 80 {
 81     if(x1<=L&&R<=x2)
 82         return SubQueryB(rt,y1,y2,1,n,1);
 83     int mid=(L+R)>>1,ans=0;
 84     if(x1<=mid)
 85         ans=MAX(ans,QueryB(x1,x2,y1,y2,L,mid,rt<<1));
 86     if(x2>mid)
 87         ans=MAX(ans,QueryB(x1,x2,y1,y2,mid+1,R,rt<<1|1));
 88     return ans;
 89 }
 90 int SubQueryS(int t,int x,int y,int L,int R,int rt)
 91 {
 92     if(x<=L&&R<=y)
 93         return tree[t].small[rt];
 94     int mid=(L+R)>>1,ans=MAXN;
 95     if(x<=mid)
 96         ans=MIN(ans,SubQueryS(t,x,y,L,mid,rt<<1));
 97     if(y>mid)
 98         ans=MIN(ans,SubQueryS(t,x,y,mid+1,R,rt<<1|1));
 99     return ans;
100 }
101 int QueryS(int x1,int x2,int y1,int y2,int L,int R,int rt)
102 {
103     if(x1<=L&&R<=x2)
104         return SubQueryS(rt,y1,y2,1,n,1);
105     int mid=(L+R)>>1,ans=MAXN;
106     if(x1<=mid)
107         ans=MIN(ans,QueryS(x1,x2,y1,y2,L,mid,rt<<1));
108     if(x2>mid)
109         ans=MIN(ans,QueryS(x1,x2,y1,y2,mid+1,R,rt<<1|1));
110     return ans;
111 }
112 int main()
113 {
114     int q,x,i,j,big,small;
115     while(~scanf("%d%d%d",&n,&b,&q))
116     {
117         Build(1,n,1);
118         for(i=1;i<=n;i++)
119         {
120             for(j=1;j<=n;j++)
121             {
122                 scanf("%d",&x);
123                 Update(i,j,x,1,n,1);
124             }
125         }
126         while(q--)
127         {
128             scanf("%d%d",&i,&j);
129             big=QueryB(i,i+b-1,j,j+b-1,1,n,1);
130             small=QueryS(i,i+b-1,j,j+b-1,1,n,1);
131             printf("%d\n",big-small);
132         }
133     }
134     return 0;
135 }
posted on 2012-06-28 11:48  DrunBee  阅读(347)  评论(0)  编辑  收藏  举报