Bzoj4552: [Tjoi2016&Heoi2016]排序

红太狼 2021-03-28 15:41 471阅读 0赞

# Sol #

二分+线段树  
巧妙啊我怎么就没想到  
二分答案，把数分类，大于等于\\(mid\\)的为\\(1\\)，小于的为\\(0\\)  
相当于给\\(01\\)序列排序，最后判断询问位置上是不是\\(1\\)  
线段树+lazy覆盖

# include <bits/stdc++.h> # define RG register # define IL inline # define Fill(a, b) memset(a, b, sizeof(a)) using namespace std; typedef long long ll; const int _(1e5 + 5); IL int Input(){ RG int x = 0, z = 1; RG char c = getchar(); for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1; for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48); return x * z; } int n, m, q, a[_], ql[_], qr[_], qo[_]; int sum[_ << 2], cov[_ << 2]; IL void Build(RG int x, RG int l, RG int r, RG int v){ sum[x] = 0, cov[x] = -1; if(l == r){ sum[x] = a[l] >= v; return; } RG int mid = (l + r) >> 1, ls = x << 1, rs = x << 1 | 1; Build(ls, l, mid, v), Build(rs, mid + 1, r, v); sum[x] = sum[ls] + sum[rs]; } IL void Pushdown(RG int x, RG int l, RG int mid, RG int r){ RG int ls = x << 1, rs = x << 1 | 1; cov[ls] = cov[rs] = cov[x]; sum[ls] = (mid - l + 1) * cov[x]; sum[rs] = (r - mid) * cov[x]; cov[x] = -1; } IL void Modify(RG int x, RG int l, RG int r, RG int L, RG int R, RG int v){ if(L <= l && R >= r){ sum[x] = (r - l + 1) * v; cov[x] = v; return; } RG int mid = (l + r) >> 1, ls = x << 1, rs = x << 1 | 1; if(cov[x] != -1) Pushdown(x, l, mid, r); if(L <= mid) Modify(ls, l, mid, L, R, v); if(R > mid) Modify(rs, mid + 1, r, L, R, v); sum[x] = sum[ls] + sum[rs]; } IL int Query(RG int x, RG int l, RG int r, RG int L, RG int R){ if(cov[x] != -1) return cov[x] * (R - L + 1); if(L <= l && R >= r) return sum[x]; RG int mid = (l + r) >> 1; if(R <= mid) return Query(x << 1, l, mid, L, R); if(L > mid) return Query(x << 1 | 1, mid + 1, r, L, R); return Query(x << 1, l, mid, L, mid) + Query(x << 1 | 1, mid + 1, r, mid + 1, R); } IL bool Check(RG int mid){ Build(1, 1, n, mid); for(RG int i = 1; i <= m; ++i){ RG int cnt = Query(1, 1, n, ql[i], qr[i]); if(!cnt || cnt == qr[i] - ql[i] + 1) continue; if(qo[i]){ Modify(1, 1, n, ql[i], ql[i] + cnt - 1, 1); Modify(1, 1, n, ql[i] + cnt, qr[i], 0); } else{ Modify(1, 1, n, ql[i], qr[i] - cnt, 0); Modify(1, 1, n, qr[i] - cnt + 1, qr[i], 1); } } return Query(1, 1, n, q, q); } int main(RG int argc, RG char* argv[]){ n = Input(), m = Input(); for(RG int i = 1; i <= n; ++i) a[i] = Input(); for(RG int i = 1; i <= m; ++i) qo[i] = Input(), ql[i] = Input(), qr[i] = Input(); q = Input(); RG int l = 1, r = n, ans = 0; while(l <= r){ RG int mid = (l + r) >> 1; if(Check(mid)) ans = mid, l = mid + 1; else r = mid - 1; } printf("%d\n", ans); return 0; }