poj2828-Buy Tickets

#include<stdio.h>
#include<string.h>
#define MAX_SIZE 200010
struct node {
    int left, right;
    int num;
};
struct person {
    int index;
    int value;
};
node tree[4*MAX_SIZE];
person que[MAX_SIZE];
int ans[MAX_SIZE];
void Build(int root, int l, int r)
{
    tree[root].left = l; tree[root].right = r;
    tree[root].num = r - l + 1;
    if(l == r) return ;
    int mid = (l + r) / 2;
    Build(root*2, l, mid);
    Build(root*2+1, mid+1, r);
}
int query(int root, int pos)
{
    tree[root].num--;
//    int mid = (tree[root].left + tree[root].right) / 2;
    if(tree[root].left == tree[root].right) 
        { return tree[root].left; }
    if(pos <= tree[root*2].num) return query(root*2, pos);
    else return query(root*2+1, pos - tree[root*2].num);
}
int main()
{
    int n;
    while(scanf("%d", &n) == 1) {
        Build(1, 1, n);
        for(int i=1; i<=n; i++) {
            int x, y;
            scanf("%d%d", &x, &y);
            que[i].index = x;
            que[i].value = y;
        }
        for(int i=n; i>=1; i--) {
            int where = query(1, que[i].index+1);
            ans[where] = que[i].value;
        }
        for(int i=1; i<=n; i++)
            printf(i==n?"%d\n":"%d ", ans[i]);
    }
    return 0;
}