poj 2828 Buy Tickets

http://poj.org/problem?id=2828

　　个人选拔的时候的题目，今天看来是水的不得了啊！~不过因为忘记换行了，搞了两个PE回来....囧...以后会注意的了。

　　题目意思不难明白，不过用线段树写要将数据倒过来处理，这样才能得到目标队列！

#include <cstdio>
#include <cstring>
#include <cstdlib>

#define lson l, m, rt << 1
#define rson m + 1, r, rt << 1 | 1

const int maxn = 200001;
int cnt[maxn << 2], mk[maxn << 2];
int bf1[maxn], bf2[maxn];
bool pr;

void up(int rt){
    cnt[rt] = cnt[rt << 1] + cnt[rt << 1 | 1];
}

void build(int l, int r, int rt){
    if (l == r){
        cnt[rt] = 1;
        return ;
    }
    int m = (l + r) >> 1;

    build(lson);
    build(rson);
    up(rt);
}

void ins(int p, int key, int l, int r, int rt){
    if (l == r){
        mk[rt] = key;
        cnt[rt] = 0;
        return ;
    }
    int m = (l + r) >> 1;

    if (p <= cnt[rt << 1]) ins(p, key, lson);
    else ins(p - cnt[rt << 1], key, rson);
    up(rt);
}

void print(int l, int r, int rt){
    if (l == r){
        if (pr) putchar(' ');
        pr = true;
        printf("%d", mk[rt]);

        return ;
    }

    int m = (l + r) >> 1;

    print(lson);
    print(rson);
}

void deal(int n){
    build(1, n, 1);
    for (int i = 0; i < n; i++){
        scanf("%d%d", &bf1[i], &bf2[i]);
    }
    for (int i = n - 1; i >= 0; i--){
        ins(bf1[i] + 1, bf2[i], 1, n, 1);
    }
    pr = false;
    print(1, n, 1);
    puts("");
}

int main(){
    int n;

    while (~scanf("%d", &n)){
        deal(n);
    }

    return 0;
}

——written by Lyon