POJ 1442 Black Box

题意：给你n个数的数列，然后再给你m次查询，第i（i<=m）次查询输入一个数c表示查询前c个数第i小是多少？c是非递减的

题解：根据Discuss说的，这题可以用各种数据结构AC...为了练习一下红黑树，我写了个红黑树求解的。240行代码，结果居然1Y了,,,这...

解法：红黑树

//不想说什么了
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int m,n;
int a[60000];
enum COLOR
{
red,black
};
struct RedBlack
{
COLOR color;
int l;
int r;
int p;
int key;
int cnt;
};
RedBlack tree[60000];
int lt;
int root;
void RB_Init()
{
tree[0].color=black;
tree[0].key=-1;
root=1;
tree[1].l=0;
tree[1].r=0;
tree[1].p=0;
tree[1].cnt=0;
tree[1].key=-1;
}
void RB_KeyC_Fixup(int x)
{
tree[x].cnt=tree[tree[x].l].cnt+tree[tree[x].r].cnt+1;
}
void RB_Left_Rotate(int x)
{
int y;
y=tree[x].r;
tree[x].r=tree[y].l;
if (tree[y].l != 0)
{
tree[tree[y].l].p=x;
}
tree[y].p=tree[x].p;
if (tree[x].p == 0)
{
root=y;
}
else if (tree[x].p != 0 && x == tree[tree[x].p].l)
{
tree[tree[x].p].l=y;
}
else if (tree[x].p != 0 && x != tree[tree[x].p].l)
{
tree[tree[x].p].r=y;
}
tree[y].l=x;
tree[x].p=y;
RB_KeyC_Fixup(x);
RB_KeyC_Fixup(y);
}
void RB_Right_Rotate(int y)
{
int x;
x=tree[y].l;
tree[y].l=tree[x].r;
if (tree[x].r != 0)
{
tree[tree[x].r].p=y;
}
tree[x].p=tree[y].p;
if (tree[y].p == 0)
{
root=x;
}
else if (tree[y].p != 0 && y == tree[tree[y].p].l)
{
tree[tree[y].p].l=x;
}
else if (tree[y].p != 0 && y != tree[tree[y].p].l)
{
tree[tree[y].p].r=x;
}
tree[x].r=y;
tree[y].p=x;
RB_KeyC_Fixup(y);
RB_KeyC_Fixup(x);
}
void RB_Insert_Fixup(int z)
{
int y;
while (tree[tree[z].p].color == red)
{
if (tree[z].p == tree[tree[tree[z].p].p].l)
{
y=tree[tree[tree[z].p].p].r;
if (tree[y].color == red)
{
tree[tree[z].p].color=black;
tree[y].color=black;
tree[tree[tree[z].p].p].color=red;
z=tree[tree[z].p].p;
}
else if (tree[y].color != red && z == tree[tree[z].p].r)
{
z=tree[z].p;
RB_Left_Rotate(z);
}
else if (tree[y].color != red && z == tree[tree[z].p].l)
{
tree[tree[z].p].color=black;
tree[tree[tree[z].p].p].color=red;
RB_Right_Rotate(tree[tree[z].p].p);
}
}
else
{
y=tree[tree[tree[z].p].p].l;
if (tree[y].color == red)
{
tree[tree[z].p].color=black;
tree[y].color=black;
tree[tree[tree[z].p].p].color=red;
z=tree[tree[z].p].p;
}
else if (tree[y].color != red && z == tree[tree[z].p].l)
{
z=tree[z].p;
RB_Right_Rotate(z);
}
else if (tree[y].color != red && z == tree[tree[z].p].r)
{
tree[tree[z].p].color=black;
tree[tree[tree[z].p].p].color=red;
RB_Left_Rotate(tree[tree[z].p].p);
}
}
}
tree[root].color=black;
}
void RB_Insert(int n)
{
int x,y;
y=0;
x=root;
while (tree[x].key != -1)
{
y=x;
tree[x].cnt++;
if (n < tree[x].key)
{
x=tree[x].l;
}
else
{
x=tree[x].r;
}
}
tree[lt].p=y;
if (y == 0)
{
root=lt;
}
else if (y != 0 && n < tree[y].key)
{
tree[y].l=lt;
}
else if (y != 0 && n >= tree[y].key)
{
tree[y].r=lt;
}
tree[lt].l=0;
tree[lt].r=0;
tree[lt].color=red;
tree[lt].key=n;
tree[lt].cnt=1;
RB_Insert_Fixup(lt);
lt++;
}
int RB_Query(int k)
{
int x,y;
x=root;
while (k != 1 || tree[x].cnt != 1)
{
// printf("->%d %d\n",k,tree[x].key);
if (k <= tree[tree[x].l].cnt && tree[x].l != 0)
{
x=tree[x].l;
}
else if (k == tree[tree[x].l].cnt+1)
{
return tree[x].key;
}
else if (k > tree[tree[x].l].cnt+1)
{
k-=tree[tree[x].l].cnt+1;
x=tree[x].r;
}
//printf("->%d %d %d\n",k,tree[x].key,tree[x].cnt);
}
return tree[x].key;
}
void printTree(int x)
{
if (tree[x].l != 0)
printTree(tree[x].l);
printf("[%d %d]\n",tree[x].key,tree[x].cnt);
if (tree[x].r!= 0)
printTree(tree[x].r);
}
int main()
{
int i,j,pr,t,p;
scanf("%d%d",&m,&n);
for (i=1; i<=m; i++)
{
scanf("%d",a+i);
}
pr=1;
p=1;
lt=1;
RB_Init();
while (n--)
{
scanf("%d",&t);
for (i=pr; i<=t; i++)
{
//  printf("i=%d\n",i);
RB_Insert(a[i]);
}
// printTree(root);
pr=t+1;
printf("%d\n",RB_Query(p));
p++;
}
}