BestCoder Round #65 C. ZYB's Premutation（线段树求第k大）

题意:

给定[1,i]前缀逆序对数,还原原始序列

分析:

先把前缀和还原成原来的,考虑倒着来,每个就相当于前面有多少个比自己大,线段树求第k大就好了,BIT什么的也可以

代码:

////  Created by TaoSama on 2015-12-05//  Copyright (c) 2015 TaoSama. All rights reserved.////#pragma comment(linker, "/STACK:1024000000,1024000000")#include <algorithm>#include <cctype>#include <cmath>#include <cstdio>#include <cstdlib>#include <cstring>#include <iomanip>#include <iostream>#include <map>#include <queue>#include <string>#include <set>#include <vector>using namespace std;#define pr(x) cout << #x << " = " << x << "  "#define prln(x) cout << #x << " = " << x << endlconst int N = 1e5 + 10, INF = 0x3f3f3f3f, MOD = 1e9 + 7;int n, a[N];int sum[N << 2], ans[N];void build(int l, int r, int rt) {    sum[rt] = r - l + 1;    if(l == r) return;    int m = l + r >> 1;    build(l, m, rt << 1);    build(m + 1, r, rt << 1 | 1);}int query(int k, int l, int r, int rt) {    --sum[rt];    if(l == r) return l;    int m = l + r >> 1;    if(k >= sum[rt << 1 | 1]) return query(k - sum[rt << 1 | 1], l, m, rt << 1);    else return query(k, m + 1, r, rt << 1 | 1);}int main() {#ifdef LOCAL    freopen("C:\\Users\\TaoSama\\Desktop\\in.txt", "r", stdin);//  freopen("C:\\Users\\TaoSama\\Desktop\\out.txt","w",stdout);#endif    ios_base::sync_with_stdio(0);    int t; scanf("%d", &t);    while(t--) {        scanf("%d", &n);        for(int i = 1; i <= n; ++i) scanf("%d", a + i);        build(1, n, 1);        int all = n;        for(int i = n; i; --i) {            int k = a[i] - a[i - 1];            ans[i] = query(k, 1, n, 1);        }        for(int i = 1; i <= n; ++i)            printf("%d%c", ans[i], " \n"[i == n]);    }    return 0;}