POJ 2828 Buy Tickets

从后往前每个找出前面恰好留出k个位置 的位置就可以。

//============================================================================
// Name        : F.cpp
// Author      : L_Ecry
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================
#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#define N 200050
using namespace std;
int sum[N * 4];
void build(int l, int r, int i) {
    sum[i] = r - l + 1;
    if (l != r) {

        int mid = (l + r) >> 1;
        build(l, mid, i << 1);
        build(mid + 1, r, i << 1 | 1);
    }
}
int update(int l, int r, int va, int i) {
    sum[i]--;
    if (l == r) {
        return l;
    }
    int mid = (l + r) >> 1;
    if (sum[i << 1] > va)
        return update(l, mid, va, (i << 1));
    else
        return update(mid + 1, r, va - sum[i << 1], (i << 1 | 1));
}
int n;
int ans[N];
int x[N], y[N];

int main() {
    while (scanf("%d", &n) != EOF) {
        build(1, n, 1);
        for (int i = 0; i < n; ++i)
            scanf("%d%d", &x[i], &y[i]);
        for (int i = n-1; i >-1; --i) {
            int tmp = update(1, n, x[i], 1);
            ans[tmp] = y[i];
        }
        for (int i = 1; i < n; ++i) {
            printf("%d ", ans[i]);
        }
        printf("%d
",ans[n]);
    }
    return 0;
}